G

2440

37P

32R

32

27

59

81O

50+27

21-51V 81U

50/5149

46

27H

59N

50G/51G

74CT

74VT

BF

26

64F

REMOTECOMMUNICATIONMODBUS TCP/IP

ON-SITEFW UPGRADE

LOCALCOMMUNICATION(OPTICAL FIBER)

BINARY INPUTS

EVENTRECORDS

SETPOINTGROUPS A-B

CB SUPERVISION

FREQUENCYTRACKING

NTG - Sheet-07-2006 1

Application

Protective functions

Construction

Measuring inputs

Metering

The NTG digital protection relay integrates a number of functions required for the protection of generators. It is used in powerstations from gas, steam, hydraulic turbine, or diesel driven generators, operating in parallel with the public network and/or in islandand with any neutral state and network layout.According to the hardware configurations BASIC and PRO, the NTG protection relay can be shipped with different sets of protectionfunctions.

21-51V Underimpedance or Voltage-controlled/restrained overcurrent24 Overexcitation (V/Hz)26 Thermal protection with 8 PT100 thermometric probes27 Undervoltage27H-59H Third harmonic Under/Overvoltage (100% stator earth fault)32 Directional active overpower32R Reverse active power37P Low forward power40 Loss of Field46 Negative sequence overcurrent49 Stator thermal image50/51 Phase overcurrent50+27 Inadvertent energization50G/51G-87N Residual overcurrent (90% stator earth fault) or, alternatively, high impedance restricted earth fault.59 Overvoltage59N Residual overvoltage (90% stator earth fault)64F Rotor earth fault81O Overfrequency81U UnderfrequencyBF Breaker failure74CT Phase CT supervision74VT Line VT supervision74TCS Trip circuit supervision

Standard 19" rack, 3U high case.Plug in terminals.

Three phase current inputs and one residual current input with nominal currents independently selectable at 1 or 5 A using jumpers.Three line voltage inputs SW programmable within the range 50...130 V or within the range 200...520 V and one residual voltageinput independently SW programmable within the range 50...130 V.Software selectable nominal frequency at 50 or 60 Hz.Rotor ground protection input with 660 Vdc maximum voltage.Eight Pt100 thermometric probe inputs.

The relay measures all the generators electrical quantities (currents, voltages, frequency, impedance, power, energies, flux, etc.)and the relay input/output logic states, making them available for reading on a display or to communication interfaces.Currents and voltages are sampled 16 times per period and measured in the effective value (RMS) of the fundamental componentusing the DFT (Discrete Fourier Transform) algorithm and digital filters.

Multifunction Generator Protection RelayNTG

NTG - Sheet-07-2006 2

Within the generator frequency range 20...75 Hz, a frequency tracking algorithm alters the currents and voltages sampling frequency,so as to keep the number of samples in any given period constant. The precision and availability of all NTG relay functions arehence even guaranteed during generator start-up and shut-down.

The relay periodically checks the phase CT and line VT circuits by measuring the line voltages and phase currents, residual andinverse sequence currents and voltages and the status of the circuit breaker. This way, any interruptions in the CT and VT secondarycircuit connections, and the tripping of any fuses or automatic circuit breakers protecting the VT itself, are monitored.The 74CT and 74VT functions, besides providing alarm signals, also provide means for blocking those generator protective functionswhich might trip as a result of any anomalies in current and voltage transformers (CT’s and VT’s).

The NTG relay comprises the following functions for monitoring and controlling circuit breaker:- Status monitoring (open, closed, anomalous).- Monitoring the trip circuit (74TCS) for any indication of trip circuit anomalies prior to the tripping of the protective devices(interruptions or absence of auxiliary voltage, interruption or short-circuiting of the trip coil).- Diagnostics: The NTG relay provides a series of cumulative data (number of operations, cumulative value of the currents brokenby each pole, cumulative I2t broken by each pole, duration of operations), to assist the user in the task of Circuit Breaker managingmaintenance programmes.

The use of flash memory units allows on-site firmware updating.

The relay protection functions have two setting parameters configurations (BANK A or BANK B). Activation of the two data sets iscontrolled binary input or communications interfaces.

With the aim of providing a selective protection system, some of the NTG relay protective functions may be blocked by logicselectivity binary input (pilot wire accelerated logic).

To avoid any over-speeding of the turbine-generator unit during shut-down of the unit or due to the delayed tripping of the protectivedevices, a binary input may be configured in order to open the machine circuit breaker as a result of tripping of the Low forwardpower (37) or Reverse power (32R) functions, only after closure of the turbine intake valve.

Upon tripping/starting of each function or on command (binary input), the relay records the last eight events. Each event includesinformation in relation to the date, time, function activated, readings, binary input and output status.

Upon trigger of tripping/starting of each function or external signals, the relay records in COMTRADE format:- oscillography with instantaneous values for transient analysis- RMS values of the measured signal for long time periods analysis- logic states (binary inputs, blocking and output signals).

The relay makes use of two communication interfaces:- a fibre-optic local communication front-end interface, used for protection management, viewing and changing the relayprogramming, obtaining readings of the logic states, the chronological events, measuring, and for relay testing and resettingcommands. The local interface is fitted as standard in all NTG relay versions.A dedicated PC Software is provided- an optional back-end interface for communication with remote monitoring and control systems by 10/100 ETHERNET using theMODBUS TCP/IP protocol and copper (RJ45) or fibre-optic (FX) connections.

Up to 16 binary inputs are available which may be used in programmable logics or for preset functions.

There are up to 16 change-over contacts Output Relays, and 24 indicator LEDs. Each final relay may be individually programmedin relation to resting state (normally energised- de-energised) and reset mode (manual or automatic). Each LED is programmablein relation to reset mode (manual or automatic). The user may program the function of each final relay and LED in accordance witha matrix (tripping matrix) structure.

The user interface comprises a membrane keyboard, a backlight LCD alphanumeric display and up to 24 LEDs. Regarding theLEDs, one are set aside to indicate auxiliary and self diagnostics power supply (green ON LED), whilst the remaining red colouredLEDs are user assigned.

All relay programming and adjustment operations may be performed using a Personal Computer with the aid of the THY-SETTERsoftware.

All hardware and software functions are repeatedly checked and any anomalies reported via display messages, communicationinterfaces, LEDs and Output Relays.Anomalies may refer to:- supply faults,- final relay coil interruptions,- non-volatile memory,- activation of trip circuit monitoring function,- activation of CT and VT monitoring functions.

Using the THY-SETTER software, it is possible to check the correct operation of each relay function without compromising generatorprotection. Verification does not include the measuring transformers, the relevant secondary circuits and the measuring inputsof the NTG relay.

Frequency tracking

CT (74CT) and VT (74VT) supervision

Circuit Breaker monitoring anddiagnostics

Firmware updating

Multiple setpoint profiles

Logic selectivity

Sequential trip logic

Sequence of events logging

Fault recording (Oscillography)

Communication

Binary inputs

Output relays and LEDs

MMI (Man Machine Interface)

Programming and settings

Self diagnostics

Testing

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

GENERAL

NTG - Sheet-07-2006 3

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Reference standards EN60255-22-2, IEC60255-22-2Electrostatic discharge- contact 6 kV- air 8 kV

Reference standards EN61000-4-8, IEC61000-4-8Magnetic field:- 50 Hz permanent 100 A/m- 50 Hz 1 s 1 kA/m

Reference standards EN61000-4-9, IEC61000-4-9Pulse magnetic field:- generator (6.4/16 µs): 1 kA/m

Reference standards EN61000-4-10, IEC61000-4-10Damped oscillatory magnetic field:- damped oscillatory 0.1 MHz 100 A/m- damped oscillatory1 MHz 100 A/m

Reference standards EN60255-22-6, IEC61000-4-6Conducted radio-frequency fields:0.15...80 MHz AM 80% 10 V

Reference standards EN60255-4-3, IEC61000-4-3Radiated radio-frequency fields:80...1000 MHz AM 80% 10 V/m900 MHz pulse modulated 10 V/m

EmissionReference standards EN61000-6-4, (ex EN50081-2)Conducted emission 0.15...30 MHz Class ARadiated emission 30...1000 MHz Class A

Climatic testsReference standards IEC60068-2

ENEL R CLI 01 CEI 50

Mechanical testsReference standards EN60255-21-1

EN60255-21-2

Environmental conditionsAmbient temperature- nominal range -10...+55 °C- storage -40...+85 °CRelative umidity 10...95 %Atmospheric pressure 70...110 kPaNOTE LCD contrast impaired for temperatures lower 0°C

Safety requirementsReference standards EN61010-1Pollution degree 3Reference voltage 250 VOvervoltage IIIPulse voltage (test) 5 kVReference standards EN60529Protection degree (Front) IP31Protection degree (Terminals) IP20

CertificationsCE conformityProtective relays EN50263EMC directive 89/336/EECLow voltage directive 73/26/EEC

Mechanical dataMounting rack 19", high 3U, depth 300 mmTerminals plug screw connectionMax conductor cross section 4 mm2Mass 7.0 kg

Insulation testsReference standards EN60255-5, IEC60255-5

EN61010Working voltage 250 VOvervoltage category III

High voltage test 50Hz ( 1 min):auxiliary power supply 2 kVinput circuits 2.5 kVoutput circuits 2 kVoutput circuits (between open contacts) 1 kV

Impulse voltage withstand test (1.2/50 µs):auxiliary power supply 5 kVinput circuits 5 kVoutput circuits 5 kVoutput circuits (between open contacts) 2.5 kV

Insulation resistance 100 MΩ

Voltage dip and interrution on d.c.Reference standards EN61000-4-29auxiliary power supply in dc energizing quantityinterruption (UT=40%) 100 msinterruption (UT=0%) 50 msvoltage variations (UT=80...120%) 10 s

EMC tests for interference immunityReference standards EN60255-22-1, IEC60255-22-1Damped oscillatory wave- 1 MHz Differential mode 1 kV- 1 MHz Common mode 2.5 kV

Reference standards EN61000-4-5, IEC61000-4-5High energy pulse (surge):open circuit voltage (1.2/50 µs) 4 kVshort circuit current (8/20 µs) 400 A- Uaux (line to earth) 2 kV- Uaux (line to line) 1 kV

Reference standards EN61000-4-12, IEC61000-4-12Damped oscillatory wave high energy (0.5 µs/0.1 MHz)- 0.1 MHz common mode 2.5 kV- 1 MHz differential mode 1 kV- ring wave common mode 2 kV- ring wave differential mode 1 kV

Reference standards EN60255-22-4, IEC60255-22-4Fast transient burst (5/50 ns) 4 kV

Reference standards EN61000-4-16Conducted common mode disturbancedc voltage 30 Vac voltage (50 Hz) 30 V0.015...150 kHz 30 V

Specifications

COMMUNICATION INTERFACES

NTG - Sheet-07-2006 4

Auxiliary power supply UauxNominal value 24 Vac/dc

48...110 Vac/dc230 Vac (1)

Range (for each one of the above 24V Vac/dc E15%nominal values) 38...150Vdc, 38...110Vac

165...265 Vac (1)Max alternating component:full wave rectified sine wave 100%sine wave 80%Maximum interruption time 0.05 sMaximum set-up time 7 sMaximum power consumption 25 VA

NOTE (1) By means DAC200 adapter

Phase current input circuitsNominal current IN 1 or 5 A selectable by jumpersPermanent overload 4 INThermal overload (1s) 100 INDinamic overload (10 ms) 250 INRated consumption (for any phase): 0.3 VA with IN = 5A

0.1 VA with IN = 1A

Residual current input circuitNominal current IEN 1 or 5 A selectable by jumperPermanent overload 4 IENThermal overload (1s) 100 IENDinamic overload (10 ms) 250 IENRated consumption: 0.3 VA with IN = 5A

0.1 VA with IN = 1A

Voltage input circuitsReference voltage UR 100 V or 400VNominal voltage UN 50...130 V or 200...520 V selectable by swPermanent overload 1.3 UR1 s overload 2 URRated consumption 0.5 VA

Residual voltage input circuitReference voltage U ER 100 VTensione Nominale U EN 50...130 V selectable by swPermanent overload 1.3 U ER1 s overload 2 U ERRated consumption 0.5 VA

Rotor earth fault input circuitsMax voltage 600 VdcMax alternating component 100 VacMax rotor earth capacitance 2 µFAuxiliary power supply 115, 230 Vac 50 Hz

Binary input circuitsQuantity 8 or 16Input voltage range 24...265 Vac/dcMax comsumption, energized 3 mA

RTD inputs (PT100)Quantity 8Range -40...240 °CTest current 1 mARefresh time 2.5 sLink 3 wiresMax lead resistance 20 Ω

Frequency trackingRange (1) 20...75 HzMinimum treshold voltage (2) 0.10 UN

NOTE (1) With input frequency out of the range, the system locks over nominal value (50 or 60 Hz)NOTE (2) U12 required for frequency traking

Phase rotationDirect L1, L2, L3

Output relaysQuantity 8 or 16Type of contacts changeover (SPDT, type C)Nominal current 5 ANominal voltage 250 VBreaking capacity:- direct current 30 W (L/R = 40 ms)- alternating current 40 W (λ= 0,4)Make 1000 W/VAShort duration current 15 A (0,5 s)Minimum switching load 50mW (5V/2mA)

Rotor earth fault outputTest voltage (open circuit) 40 VacFrequency 50 HzTest current (short circuit) 0.15 A

Display LCD 16x2 characterLEDs 16 or 24Keyboard 8 keys

Local PC- Connection Optical Fiber- Rate 19.2 kBps- Parity None- Protocol Modbus RTU

Network Ethernet 100 Base TX, 100 Base FX- Connection RJ45

Optical Fiber 820nm FX- Protocol Modbus TCP/IP

INPUT CIRCUITS

MMI

OUTPUT CIRCUITS

GENERAL SETTINGS

FUNCTIONS

NTG - Sheet-07-2006 5

FUNCTIONS

Nominal frequency 50, 60 Hz

Phase nominal current IN 1A, 5A (settable by means jumpers)

Phase nominal primary currentof the phase CTs INP 1A...10 kA

(1...499 A steps 1A500...4990 A steps 10 A5...10 kA steps 100 A)

Residual nominal current I EN 1A, 5A (settable by means jumpers)

Residual nominal primary currentof the residual CT I ENP 1A...10 kA

(1...499 A steps 1A500...4990 A steps 10 A5...10 kA steps 100 A)

Generator nominal current ING 1A...10 kA(1...499 A steps 1A500...4990 A steps 10 A5...10 kA steps 100 A)

Phase nominal voltage UN 50 V...130 V (UR = 100 V)200 V...520 V (UR = 400 V)step 1V

Phase nominal primary voltageof the VT UNP 50 V...500 kV

(50...499 V steps 1V500...4990 A steps 10 V5.0...49.9 kV steps 100 V50...500 kV steps 1 kV)

Generator nominal voltage UNG 50 V...500 kV(50...499 V steps 1V500...4990 A steps 10 V5.0...49.9 kV steps 100 V50...500 kV steps 1 kV)

Residual nominal voltage UEN 50 V...130 V (U ER = 100 V)steps 1V

Residual nominal primary voltageof the residual VT UENP 50 V...500 kV

(50...499 V steps 1V500...4990 A steps 10 V5.0...49.9 kV steps 100 V50...500 kV steps 1 kV)

Base current I B 0.40...1.50 IN steps 0.01 IN

Underimpedence (21)

Pickups Z<, Z<< 0.02...3.00 ZNsteps 0.01 ZN

Time delays tZ<, t Z<< 0.07...100.0 s(definite time) (0.07...9.99 s s teps 0.01 s,

10.0...100.0 s s teps 0.1 s)Reset time delays tZ<RES, t Z<<RES 0.00...100.0 s

(0.00...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Pickup times 0.05 sDropout ratio 1.03...1.08Dropout time 0.05 sOvershoot time 0.02 sReference values rest: 0

operation: 1.5 I T (1)Pickup accuracy E4% + 0.5% ZNTime delays accuracy E1% E 8 ms

NOTE (1) I T stands for the input current needed to rise a trip according to a given setting and a giveninput voltage

Overexcitation (24)

Pickups (U/ f )AL, (U/ f )>, (U/ f )>> 0.50...2.00 UN/ fNs teps 0.01 UN/ fN

Time delays tU/fAL,tU/f>,tU/f>>(definite time) 0.10...100.0 s

(0.10...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Time delay tU/f>(inverse time IEC curvesnormal inverse (A),very inverse (B)estremely inverse (C))(1) 0.10...60.0 s (2)

(0.10...9.99 s steps 0.01 s,10.0...60.0 s steps 0.1 s)

Reset time delay tU/f>RES 0.00...1000 s(0.00...0.99 s steps 0.01 s,10.0...9.99 s steps 0.1 s,100...1000 s steps 1 s)

Pickup times 0.05 s for pickups (U/ f )AL, (U/ f )>>,0.07 s for pickup (U/ f )>

Dropout ratio 0.95...0.98Dropout time 0.07 s for pickups (U/ f )AL, (U/ f )>>,

0.06 s for pickup (U/ f )>Overshoot time 0.03 sRiference values rest: 0

operation:2.5 pickup value for definite time,1.5 pickup value for inverse time curves

Pickup accuracy E4% + 1% UN/ fNTime delays accuracy E1% E 8 ms for definite time,

2.5% E 8 ms for IEC type A curve,5% E 8 ms for IEC type B curve,7.5% E 8 ms for IEC type C curve,

NOTE (1) DEP A: inverse time IEC, t=0.0081tU/f>/[(U/ f )/(U/ f )>0.02-1]DEP B: very inverse time IEC, t=0.5tU/f>/[(U/ f )/(U/ f )>)-1]DEP C: extremely inverse time IEC, t=1.25tU/f>/[(U/ f )/(U/ f )>)2-1]

Pickup threshold: 1.1 (U/ f )>The curves are defined between 1.1 and 5 multiples of pickup (U/ f )> with a maximum of UN/ fN.Minimum operating time: 0.1 s

NOTE (2) Time delay tU/f> is the operating time corrisponding to U/ f = 1.5(U/ f )>

Thermal protection with RTD thermometric probes (26)

Pickups PTxAL, PTx> (x=1...8) 0...200 °Cs teps 1 °C

Time delays tPTxAL, tPTx>(with definite time characteristic) 0....100 s steps 1 sPickup accuracy E1°CTime delays accuracy E1% E 8 msUpdate rate £ 0.25 s

Undervoltage (27)

Common configurations:- Measured voltages Phase-to-phase/Phase-to-ground- Operating criteria OR/AND(1)

Pickups U<, U << 0.05...1.10 UNsteps 0.01 UN

Time delays tU<, tU<<(with definite time characteristic) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Time delay tU<(with inverse time characteristic)(2) 0.10...100.0 s (3)

(0.10...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 sDropout ratio 1.03...1.08Dropout time 0.06 s for U< pickup

0.07 s for U<< pickupOvershoot time 0.02 s

NTG - Sheet-06-2006 6

Reference values rest: 1.2 U<, U<<operation: 0.8 U<, U<<

Pickup accuracy E3% + 0.05% UNTime delay accuracy E1% E 8 ms for definite time,

5% E 8 ms for inverse time,

NOTE (1) Start and trip criteria: - OR the element operates when al least one of the voltages falls below the set pickup, - AND the element operates when all the voltages falls below the set pickup

NOTE (2) Inverse time characteristic t=0.75tU</[1-(U/U<)]Maximun pickup value is 0.9U< The curve is defined between 0 and 0.9 U< multiples of pickup.Minimum operating time: 0.1 s

NOTE (3) Time delay tU< is the operating time corrisponding to t U = 0.25U<

100% stator earth-fault with 3rd harmonic (27H-59H)

Pickups UE3H<, UE3H> 0.003...0.400 UENsteps 0.001 UEN

Time delays t E3H<, t E3H>(definite time) 0.07...100.0 s

(0.07...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Pickup times 0.05 sDropout ratio 1.03...1.08 for the 27H function

0.95...0.98 for the 59H function

Drop-off time 0.06 sOvershoot time 0.02 sRiference values 27H rest: 1.2 UE3H<

operation: 0.8 UE3H<Riference values 59H rest: 0.8 UE3H>

operation: 1.2 UE3H>Pickups accuracy E3% + 0.5% UENTime delays accuracy E1% E 8 msInhibit threshold U IN-3H< 0.10...1.10 UN

steps 0.01 UNInhibit threshold I IN-3H< 0.05...1.50 IN

s teps 0.01 IN

Active directional overpower (32)

Pickup P+> 0.10...1.50 PNsteps 0.01 PN

Time delay tP+>(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup time 0.05 sDrop-off ratio 0.95...0.98Drop-off time 0.06 sOvershoot time 0.02 sRiference values rest: 0.8 P+>

operation: 1.2 P+>Pickup accuracy E4% + 0.5% PNTime delay accuracy E1% E 8 ms

Active reverse power (32R)

Pickup P-> -0.01...-1.00 PNsteps 0.01 PN

Time delay tP->(definite time) 0.07...100.0 s

(0.07...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Pickup P->> -0.01...-1.00 PNsteps 0.01 PN

Time delay tP->>(definite time) 0.07...100.0 s

(0.07...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Reset time delay tP->RES, tP->>RES 0.0...100.0 s(0.00...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Pickup times 0.05 sDropout ratio 0.95...0.98Dropout time 0.06 sOvershoot time 0.02 sReference values rest: 0.8 P->, P->>

operation: 1.2 P->, P->>Pickup accuracy E4% + 0.5% PNTime delay accuracy E1% E 8 ms

Low forward power (37P)

Pickup P+< 0.01...1.20 PNsteps 0.01 PN

Time delay tP+<(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup time 0.05 sDropout ratio 1.02...1.05Dropout time 0.06 sOvershoot time 0.02 sReference values rest: 1.2 P+<

operation: 0.8 P+<Pickup accuracy E4% + 0.5% PNTime delay accuracy E1% E 8 ms

Loss of Field (40)

Inclination angle Alpha (alarm pickup) 10...75°s teps 1°

Undervoltage threshold USUP< 0.50...1.00 UNOffset thresholds XO1, XO2 -2.00...2.00 ZNF(1)

s tep 0.01 ZNFDiameter threshold XD1, XD2 0.20...5.00 ZNF

s teps 0.01 ZNFTime delays tAL, t1<, t2<(definite time) 0.07...100.0 s

(0.07...9.99 s s teps 0.01 s,10.0...100.0 s s teps 0.1 s)

Reset time delay t1RES<, t2RES< 0.0...10.0 sstep 0.1 s

Pickup times 0.05 sDropout ratio 0.95...0.98Dropout time 0.06 sOvershoot time 0.02 sA la rm reference values rest: R=0, X=0.5 ZNF

operation: R=0, X=1,0 ZNFTr ip reference values rest: R=0, X=0 ZNF

operation: circle centerPickups accuracy RE4% + 0.5% ZNF

XE4% + 0.5% ZNFTime delays accuracy E1% E 8 ms

NOTE (1) ZNF = EN/IN, where EN is the phase-to-earth voltage

NTG - Sheet-07-2006 7

Negative sequence overcurrent (46)

Pickup I2AL>(definite time) 0.03...0.50 IB

s teps 0.01 IBTime delay t2AL>(definite time) 0.10...100.0 s

(0.10...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup I 2>>(inverse time) (1) 0.05...0.50 IB

s teps 0.01 IBHeating time constant Kheat (2) 0.1...40.0 s

s teps 0.1 sCooling down time Kcool 0.1...40.0 s

s teps 0.1 sMinimum operating time t2min 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Max operating time t2max 500...2000 ssteps 10 s,

Pickup times 0.05 s for I 2AL> threshold,0.07 s for I 2AL>> threshold

Dropout ratio 0.95...0.98Dropout time 0.06 s for I 2> threshold,

0.07 s for I 2>> threshold,Overshoot time 0.03 sReference values rest: 0

operation: 1.5 IAL>, I 2>>Pickups accuracy E4% + 1.0% INTime delays accuracy E1% E 8 ms for definite time,

E5% E 8 ms for inverse time curve

NOTE (1) Inverse time characteristic t=Kheat/(I 2/ IB)2Te curve is defined between 1 and 100 multiples of I B with a maximum of 30 INMinimum operating time: 0.1 s

NOTE (2) The heating time constant Kheat is the operating time corrisponding to I 2=lIB

Stator thermal image (49)

Heating time constant τ+ (T1) 1...200 mins teps 1 min

Cooling time constant τ- (T2) 1.0...6.0 τ+steps 0 .1 τ+

Pickup DTheta Alarm DThetaAL 0.3...1.1 ∆θB (DThetaB)s teps 0.1 ∆θB

Pickup ∆θ> (DTheta>) (1) 1.2 ∆θBThermal image preset DThetaIN 0.0....1.0 DθB

steps 0.1 ∆θBHeating coefficient relative tonegative sequence current K2 0...10

s teps 1Dropout ratio 0.95...0.98Pickups accuracy E5%Time delays accuracy E7.5% E 8 ms

NOTE (1) Inverse time characteristic t=t+ln[(I th/IB)2-p2]/[(I th/IB)2-1.2] with preload p,

I th= w (I 12+k2I22) equivalent thermal current

I1 positive sequence current, I2 negaitive sequence current

The curve is defined between 1.1 and 10 multiples of I B with a maximum of 20 IB.Between 10IB and 10 IB the operating time is costant (corrisponding to 20 IB)

∆θB (DThetaB) Basic overtemperature: it represents the overtemperature corresponding to the base current I B

Phase overcurrent (50/51)

Pickup I> 0.100...5.00 IN(definite time or inverse time) (0.100...0.999 IN steps0.001 IN,

1.00...5.00 IN steps 0.01 IN)Time delay t>(definite time) 0.05...200 s

(0.05...9.99 s risoluzione 0.01 s,10.0...99.9 s risoluzione 0.1 s,100...200 s risoluzione 1 s)

Time delay t>(inverse time IEC curvesnormal inverse (A),very inverse (B)estremely inverse (C) and I2t (1) (3) 0.10...60.0 s (2) (3)

(0.10...9.99 s steps 0.01 s,10.0...60.0 s steps 0.1 s)

Pickup I>>(definite time or inverse time I2t) (3) 0.100...20.0 IN

(0.100...0.999 IN steps 0.001 IN,1.00...9.99 IN steps 0.01 IN,10.0...20.0 IN steps 0.1 IN)

Time delay t>>(definite time) 0.04...10.00 s steps 0.01 sTime delay t>>(inverse time I2t) (3) 0.10...10.0 s

steps 0.01 sPickup I>>> 0.100...20.00 IN

(0.100...0.999 IN steps 0.001 IN,1.00...9.99 IN steps 0.01 IN,10.0...20.0 IN steps 0.1 IN)

Time delay t>>>(definite time) 0.04...10.00 s

steps 0.01 sReset time delay t I>RES,t I>>RES,t I>>>RES 0.00...100.0 s

(0.00...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 s for I> threshold,0.03 s for I>>, I>>> thresholds

Dropout ratio 0.95...0.98Dropout time 0.06 s per la soglia I>,

0.07 s per le soglie I>>, I>>>Overshoot time 0.03 sReference values rest: 0

trip: 1.5 I>, 2.5 I>>, 2.5 I>>>Pickups accuracy E4% + 1.0% INTime delays accuracy E1% E 8 ms for definite time,

2.5% E 8 ms for IEC type A curve,5% E 8 ms for IEC type B curve,7.5% E 8 ms for IEC type C curve,7.5% E 8 ms for I2t constant curve

NOTE (1) DEP A: inverse time IEC, t=0.028t >/[(I/ I >)0.02 - 1]DEP B: very inverse time IEC, t=3t >/[(I/ I >) - 1]DEP C: extremely inverse time IEC, t=15t >/[(I/I >)2 - 1]DEP I2t: curva I 2t costante t=16t >/ (I/ I>)2

Pickup threshold: 1.1 I >The curves are defined between 1.1 and 20 multiples of pickup I > with a maximum of 30 I NMinimum pickup time: 0.1 s

NOTE (2) Time delay t > is the operating time corrisponding to I =4 I >

NOTE (3) DEP I2t: I 2t constant characteristic t=16t >>/ (I/ I >>)2Pickup threshold: 1.1 I >>The curves are defined between 1.1 and 20 multiples of pickup I >> with a maximum of 30 I NMinimum pickup time: 0.1 s

NTG - Sheet-07-2006 8

Inadvertent energization (50+27)

Pickup IUE> 0.05...4.00 INstep 0.01 IN

Pickup UUE< 0.10...1.00 UNtep 0.01 UN

Time delay tUE(definite time) 0...10.0 s

step 0.01 sReset time delay tUE-RES 0.0...10.0 s

step 0.01 sPickup time 0.05 s for I UE> threshold,

0.05 s for UUE< thresholdDropout ratio 0.95...0.98 for I UE> threshold

1.02...1.05 for UUE< thresholdDropout time 0.06 s for I UE>, UUE< thresholdsOvershoot time 0.03 sReference values rest: 0 for I UE> threshold,

operation: 1.5 IUE> for IUE> thresholdrest: 1.2 for UUE< threshold,operation: 0.8 IUE> for UUE< threshold

Pickups accuracy E4% + 1.0% INE3% + 0.05% UN

Time delay accuracy E1% E 8 ms

Residual overcurrent (50G/51G) / Restricted earth fault (87N)

Pickup I E> 0.010...2.00 I EN(0.010...0.999 IEN steps 0.001IEN1.00...2.00 I EN steps 0.01 I EN)

Time delay t E> (definite time) 0.05...200 s

(0.05...9.99 s steps 0.01 s,10.0...99.9 s steps 0.1 s,100...200 s steps 1 s)

Time delay t E>(inverse time IEC curvesnormal inverse (A),very inverse (B)estremely inverse (C))(1) 0.10...60.0 s (2)

(0.10...9.99 s steps 0.01 s,10.0...60.0 s steps 0.1 s)

Pickups I E>> and I E>>>(definite time) 0.010...10.00 I EN

(0.010...0.999 IEN steps 0.001IEN1.00...10.00 I EN steps 0.01 I EN)

Time delays t E>> and t E>>>(definite time) 0.05...10.0 s

steps 0.01 sReset time delays tIE>RES, tIE>>RES, tIE>>>RES0.0...100.0 s

(0.00...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.06 s for I E> threshold,0.04 s for I E>>, I E>>> thresholds

Dropout ratio 0.95...0.98Dropout time 0.07 s for I E> threshold,

0.08 s for I E>>, I E>>> thresholdsOvershoot time 0.03 sReference values rest: 0

operation: 1.5 IE>, 2.5 IE>>, 2.5IE>>>Pickups accuracy E4% + 1.0% IENTime delays accuracy E1% E 8 ms for definite time,

2.5% E 8 ms for IEC type A curve,5% E 8 ms for IEC type B curve,7.5% E 8 ms for IEC type C curve

NOTE (1) DEP A: inverse time IEC, t=0.028tE>/[(I E/ I E>)0.02 - 1]DEP B: very inverse time IEC, t=3tE>/[(I E/ IE>) - 1]DEP C: extremely inverse time IEC, t=15tE>/[(I E/ I E>)2 - 1]

Pickup threshold: 1.1 I E>The curves are defined between 1.1 and 20 multiples of pickup I E> with a maximum of 15I ENMinimum pickup time: 0.1 s

NOTE (2) Time delay t> is the operating time corrisponding to I = 4IE>

Voltage-controlled / restrained overcurrent (51V)

Common configurations:- Operating mode Voltage Controlled/Voltage Restraint - Pickup U-51CV< 0.10...1.00 UN

steps 0.01 UN- Pickup U1-51AV< 0.10...1.00 UN

steps 0.01 UN- Pickup U2-51AV< 0.10...1.00 UN

steps 0.01 UN- Reduction factor K 0.10...1.00

steps 0.01Pickup I -51V> 0.20...10.00 IN

steps 0.01 INTime delay tI -51V>(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s

Pickup I -51V>> 0.20...20.00 INsteps 0.01 IN

Time delay t I -51V>>(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s

Reset time delays t I-51V>RES, t I-51V>>RES 0.0...100.0 s(0.00...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.06 sDropout ratio 0.95...0.98Dropout time 0.07 sOvershoot time 0.03 sReference values rest: 0

operation: 1.5 I TPickups accuracy E5%Time delays accuracy E1% E 8 ms

NOTE (1) I T is the current input value needed to trip

Overvoltage (59)

Common configurations:- Measured voltages Phase-to-phase/Phase-to-ground- Operating criteria OR/AND(1)

Pickups U >, U >> 0.50...1.50 UNsteps 0.01 UN

Time delays tU>, tU>>(definite time) 0.10...100.0 s

(0.10...9.99 s risoluzione 0.01 s,10.0...100.0 s risoluzione 0.1 s)

Time delay tU>(inverse time) (2) 0.07...100.0 s (3)

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.04 sDropout ratio 0.95...0.98Dropout time 0.07 sOvershoot time 0.03 sReference values rest: 0.8 U >, 0.8 U >>

operation: 1.2 U >, 1.2 U >>Pickups accuracy E3% + 0.05% UNTime delays accuracy E1% E 8 ms for definite time,

E5% E 8 ms for inverse time curve,

NOTE (1) Start and trip criteria: - OR the element operates when al least one of the voltages exceeds the set pickup, - AND the element operates when all the voltages exceeds the set pickup

NOTE (2) Inverse time curve t=0.5tU>/[(U /U>) - 1]Pickup threshold: 1.1U>The curve is defined between 1.1 and 4 multiples of pickup U > with a maximum of 2U NMinimum pickup time: 0.1 s

NOTE (3) Time delay tU> is the operating time corrisponding to I = 1.5U>

NTG - Sheet-07-2006 9

Residual overvoltage (59N)

Pickups UE>, UE>> 0.01...0.50 UENsteps 0.01 UEN

Time delays tUE>, tUE>>(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Time delay tUE>(inverse time) (1) 0.10...100.0 s (2)

(0.10...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Reset time delay tUE>RES, tUE>>RES 0.0...100.0 s(0.00...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 sDropout ratio 0.95...0.98Dropout time 0.08 sOvershoot time 0.03 sReference values rest: 0

oprration: 1.5 UE>, 1.5 UE>>Pickups accuracy E3% + 0.05% UENTime delays accuracy E1% E 8 ms for definite time,

E5% E 8 ms for inverse time curve

NOTE (1) Inverse time curve t=0.5tUE>/[(U /UUE>) -1]Pickup threshold: 1.1UE>

The curves are defined between 1.1 and 4 multiples of pickup UE>Minimum pickup time: 0.1 s

NOTE (2) Time delay tUE> is the operating time corrisponding to I = 1.5UE>

Rotor earth fault (64F)Pickups RFAL<, RF<< 0.50...5.00 kΩ

steps 0.01 kΩTime delays tRFAL<, tRF<<(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 sDropout ratio 1.02...1.05Dropout time 0.08 sOvershoot time 0.03 sReference values rest: R=h

operation: 2/3 RFAL<, RF<<Pickups accuracy E3% + 20 ΩTime delays accuracy E1% E 8 msField/Exciter supply voltage rating 660 Vdc

Overfrequency (81O)

Pickups f>, f>> 1.000...1.200 fNsteps 0.002 fN

Time delays t f>, t f>>(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 sPickup/dropout difference 0.3...0.5 HzDropout time 0.06 sOvershoot time 0.03 sReference values rest: 0.9 f>,

operation: 1.1 f>, 1.1 f>>Pickups accuracy E50 mHzTime delays accuracy E1% E 20 ms

Underfrequency (81U)

Pickups f<, f<<, f<<<, f<<<< 0.800...1.000 fNsteps 0.002 fN

Time delays t f<, t f<<, t f<<<, t f<<<<(definite time) 0.07...100.0 s

(0.07...9.99 s steps 0.01 s,10.0...100.0 s steps 0.1 s)

Pickup times 0.05 sPickup/dropout difference 0.3...0.5 HzDropout time 0.06 sOvershoot time 0.03 sReference values rest: 1.1 fN,

operation:0.9 f<, 0.9f<<, 0.9 f<<<, 0.9 f<<<<

Pickups accuracy E50 mHzTime delays accuracy E1% E 20 ms

Breaker failure (BF)

Pickup IBF> 0.05...1.00 INsteps 0.01 IN

Pickup I EBF> 0.01...2.00 I ENsteps 0.01 I EN

Time delay tBF(definite time) 0.06...10.00 s

steps 0.01 sPickups accuracy IBF> E4% + 1.0% INPickups accuracy I EBF> E4% + 1.0% INTime delays accuracy E1% E 8 ms

VT Supervision (74VT)

Pickup U2VT> 0.05...0.50 E Nsteps 0.01 E N

Pickup I2VT> 0.05...0.50 INsteps 0.01 IN

Pickup UVT< 0.05...0.50 E Nsteps 0.01 E N

Pickup UVT> 0.05...0.50 E Nsteps 0.01 E N

Pickup DI VT< (DeltaI VT<) 0.05...0.50 INsteps 0.01 IN

Pickup I VT> 0.10...40.0 IN(0.100...0.999 IN steps 0.001 IN,1.00...9.99 IN steps 0.01 IN,10.0...40.0 IN steps 0.1 IN)

Time delay tVT-AL 0.0...10.0 ssteps 0.1 s

Pickups accuracy I 2VT>,DI VT< ,I VT> E4% + 1.0% INPickups accuracy U2VT>, UVT<, U VT> E3% + 0.5% E NTime delays accuracy E1% E 8 ms

CT Supervision (74CT)

Pickup I ECT> 0.08...4.00 INsteps 0.01 IN

Pickup UECT< 0.01...0.50 UENsteps 0.01 UEN

Time delay tCT-AL 0.0...10.0 ssteps 0.1 s

Pickup accuracy I ECT> E4% + 1.0% IENPickup accuracy UECT< E3% + 0.5% UN

Time delays accuracy E1% E 8 ms

OPERATIONAL MEASURED VALUES

NTG - Sheet-07-2006 10

Frequency

Range 20...72 HzAccuracy E0.1% fN

Currents

Phase I L1, I L2, I L3 0.020...30.0 INAccuracy 3%E0.5% INResidual I E (measured) 0.010...15.00 I ENAccuracy 3%E0.1% IENResidual I E (computed) 0.010...15.00 I ENAccuracy 5%E0.5% IENDirect sequence I1 0.01...30.0 INAccuracy 4%E1% INInverse sequence I2 0.01...10.00 INAccuracy 4%E1% INThermal image ∆θ 0.01...1.20 ∆θBAccuracy 5%

Voltages

Phase-to-earth U L1, U L2, U L3 0.01...2.00 UNAccuracy 3%E0.05% UNPhase-to-phase U 12, U 23, U31 0.01...2.00 UNAccuracy 3%E0.05% UNResidual voltage U E 0.05...2.00 UENAccuracy 3%E0.05% UENInverse sequence U2 0.05...2.00 E NAccuracy 5%E0.1% IN3rd harmonic residual UE3H 0.003...1.000 UENAccuracy 3%E0.05% UENFlux UMAX/f 0.50...10.00 UN/fNAccuracy 4%E1% UN/fN

Impedance

Impedance Z12,Z23,Z31 (21 element) 0.01...10.00 ZNAccuracy 4%E0.5% ZNImpedance Z (40 element) 0.01...10.00 ZNFAccuracy 4%E0.5% ZNFZ Resistive component ERZ -10.00...+10.00 RNAccuracy 4%E0.5% ZNZ Reactive component EXZ -10.00...+10.00 XNAccuracy 4%E0.5% ZNZ Power factor cosPhi-Z -1.00...+1.00Accuracy 5%

Temperature

Diagnostic PT1...PT8 ON, LOW, HIGHRange PT1...8 -40...240 °CAccuracy 1 °C

Power

Phase active power PL1,PL2,PL3 -3.00...+3.00 PNAccuracy 4%E0.5% PNActive power P -3.00...+3.00 PNAccuracy 4%E0.5% PNReactive QL1,QL2,QL3 -3.00...+3.00 QNAccuracy 4%E0.5% QNReactive Q -3.00...+3.00 QNAccuracy 4%E0.5% QNApparent SL1,SL2,SL3 -3.00...+3.00 SNAccuracy 4%E0.5% SNApparent S -3.00...+3.00 SNAccuracy 4%E0.5% SNPhase power factor cosPhi-L1...3 -1.00...+1.00Accuracy 5%

Insulation resistance (excitation circuit)

Field insulation resistance RF 0.50...5.00 kΩAccuracy E3% + 20 Ω

Binary inputs

Binary inputs IN1...16 ON/OFFFailure Present/Not presentDelayed binary inputs IN1...16 ON/OFFFunction binary input ON/OFFBlock2 inputs ON/OFFBlock2 outputs ON/OFFOutput Functions ON/OFFOutput relays K1...K16 ON/OFFFailure Present/Not present

Counters

Partial counters 0...10 000Total counters 0...10 000

Events

Data, timeEvent causePhase and residual currents I L1, I L2, I L3, I L3Phase-to-earth and phase-to-phase voltages UL1, UL2, UL3, U12, U23, U31Residual voltage U E and related third component UE3HTotal active power PPhase active, reactive, apparent powers PL1...L3, QL1...L3,SL1...L3Power factors cosPhi-L1...L3Positive and negative sequence currents I1, I2Impedance Min Z12, Z23 e Z31 (40 element)Resistive an reactive components ER, EX of ZPower factor of Z cosPhi-ZPower frequency fRotor fault resistance RFThermal image DThetaFlux Umax/fPT1...8 temperatureInputs and outputs

Oscillography

File format COMTRADERecords 1x9600 to 600x16 cyclesRecording mode linearSampling rate 16 samples per periodTrigger setup:- source binary inputs (IN1...IN16)

communication (ThySetter)outputs (K1...K16)

- pre-trigger 0.05...1.00 s- post-trigger 0.05...60.00 sRecorded data inside 8 sampled channels:- instantaneous currents L1, iL2, iL3, iE- instantaneous voltages uL1, uL2, uL3, uERecorded data inside 12 analog channels:- frequency f- RMS currents IL1, IL2, IL3, IE(meas. & calc.), I1, I2- RMS voltages UL1, UL2, UL3, UL12, UL23, U2- RMS residual voltage and 3rd harmonic UE, UE3H- flux Umax/f- ithermal image DTheta- insulation resistance of the exitation field RF- powers P, PL1...L3, QL1...L3,SL1...L3, cosPhi-L1...L3- impedance and R and X components Z12, Z23, Z31, Z, R, X, cosPhi-z- thermal probe temperatures PT1...PT8Recorded data inside 12 digital channels:- outputs (relays) K1...K16- binary inputs IN1... IN16

NTG - Sheet-07-2006 11

A reset timer tU/fRES, joined to first threshold(U/f )>, allows reproduction of the machine cooling;clearing of the timer can be issued by bynary inputor communication command.

The element is enabled within the 20...75 Hzfrequency range.

Each of the two thresholds may be associatedwith the breaker failure (BF) function.

The logical block for each of the two thresholdsmay be programmed from a binary input.

Underimpedance (21)Underimpedance protection is typically used to

protect the generator against short-circuit betweenphases outwith the differential protection area 87Gand as a backup to the latter.

It is frequently used in place of voltage-dependentOvercurrent protection 51V when coordination withdistance measuring protective devices is requiredon the HV step-up transformer side.

The device performs the three-phasemeasurement of impedance and uses twoindependently settable (Z<, Z<<) and delayed (tZ<and t Z<<) thresholds, both having circularcharacteristics within the plane R, X and atindependent times.

Current measurement may be performed withphase CT located on the generator star point side orline side, but location on the star point side is to bepreferred so that protection of the generator isactive even with the circuit breaker open.

Tripping the first threshold Z< may be inhibitedby tripping of the second threshold Z<<.

The first threshold Z< is used for protectionagainst short-circuit between the phases to thegenerator bus-bar, in the first part of the statorwindings of the generator itself and the MV sidewindings of the step-up transformer.

The second threshold Z<< performs protectionof the step-up transformer up to the HV side.

There is an adjustable reset time, common toboth protection thresholds (t ZRES) useful forcoordination with electromechanical relays, in orderto increase sensitivity against swings between thegenerator and the network or to reduce intermittentfault clearing times.

Protection is enabled for each phase withfrequency in the 20...75 Hz range if the correspondingvoltages and currents exceed 1% UN and 5% INrespectively.

Both protection thresholds are blocked uponactivation of the VT monitoring function (74VT).

Each of the two thresholds may be associatedwith the breaker failure (BF) function .

The logical block and/or blocking by logicselectivity may be programmed for each of the twothresholds from one or more binary inputs.

Overexcitation V/Hz (24)Overexcitation protection is used to protect thegenerator and possibly the transformer connectedto it (e.g. step-up or auxiliary services transformer),against loss of insulation between the magneticcircuit core plates resulting from overheating producedby iron loss due to increased induction (over-excitation).Over-excitation may occur:- with generators disconnected from the networkduring start-up or standing, due to automatic controlof the voltage regulator which, at low frequency,forces excitation increasing the flux in order to keepthe voltage constant,- due to breakdown of the voltage regulator while inautomatic control mode or due to improper operationwhile in manual control mode,- following the over-voltage produced by the sheddingof a significant load, whilst the voltage regulator isnot operating sufficiently quickly to reduce the over-voltage.

The device measures the relationship U/f, whichis proportion to the magnetic flux, the calculation isbased on the ratio between the maximum voltage ofthe three phase to phase voltages and the frequency.

To better adapt itself to the limit curve of theadmissible induction of the generator and transformer,the protective device makes use of an alarm (U/f )ALand two, independently settable and delayed(tU/f>,tU/f>>), trip thresholds (U/f )> and (U/f )>>.Tripping of the first trip threshold (U/f )> may beinhibited by tripping of the second threshold (U/f )>>(the alarm threshold is always inhibited by trippingof the first or second thresholds).

The first trip threshold (U/f )> may be programmedat definite or inverse times according to the inverse,very inverse or extremely inverse time IEC 60255curves.

t

ZZ << Z <

t Z<<

t Z<

t

U/f(U/ f ) AL

t U/fAL

t U/f>>

t U/f>

(U/ f )> (U/ f )>>

1.1(U/ f )>

R

X

TRIP

NO TRIP

Z<

Z<<

TRIP

R,X tripping characteristic of the impedance protection (21)

FUNCTIONS

NTG - Sheet-07-2006 12

t

PTxAL

tPTxAL

tPTx>

PTx> T °C

Thermal protection with PT100 thermometricprobes (26)A direct thermal protection element with eight PT100thermometric probes (RTD Resistive Thermal Device)provides protection against premature ageing orbreakdown of the insulating materials throughoverheating.The probes should be placed in strategic pointsaround the machinery susceptible to the greatestoverheating, such as for example:- near the generator stator windings, near the step-up transformer windings and/or in the oil, with theaim of detecting overheating produced by the overloadcurrents,- near the generator bearings, with the aim ofdetecting localised overheating due to worn or non-lubricated bearings.Thermal protection using thermometric probesoffers greater reliability than Thermal overload-basedindirect protection, since it is not influenced byinaccuracies in the time constant for the thermalmodel of the machinery and by variations in thesurrounding temperature.Each of the eight thermometr ic probeshas independently settable and delayed(tPTxAL, tPTx>, x=1...8) alarm (PTxAL, x=1...8) andtrip (PTx>,x=1...8) thresholds.

Each threshold may be associated with the breakerfailure (BF) function.An alarm indicates any interruption or short-circuitingof the probe or related connections to the NTG relay.

Undervoltage (27)The Undervoltage function may be used for variouspurposes:- in a programmable logic,- as backup protection against short circuits,- as protection against extended voltage reductionswith the generator operating in island network, dueto failure of the automatic voltage regulator,- as protection when the voltages on the generatorbus-bars, from which its own auxiliary services aresupplied (boiler feed, cooling and lubrication pumps),drops to values where performance of the machineryis reduced to unacceptable limits.Three phase measurement of the phase voltages orthe phase to phase voltages may be selected, justas with the protection element operating logic ("AND"or "OR" of the three voltages).There are two independently settable (U<, U<<) and delayed (tU<, tU<<) thresholds, of which the firsthas definite time or inverse time characteristics,whilst the second is definite time.

First threshold U< tripping may be inhibited by secondthreshold U<< tripping.The device is enabled within the 20...75 Hz frequencyrange.

Both protection thresholds are blocked upon activationof the VT monitoring function (74VT).Each of the two thresholds may be associated withthe breaker failure (BF) function.A logical block may be programmed by a binary inputfor each of the two thresholds, thus avoiding thetripping of the protective element during generatorshut-down or due to faults in the VT secondary circuit(in this case, the logical input must be controlled bythe secondary circuit automatic breaker switch).

100% stator earth-fault with 3rd harmonic:residual under-overvoltage (27H-59H)

The protective device, used in conjunction with the90% stator ground (50G/51G or 59N) protectiveelement, extends protection against breakdown ofthe insulation towards the generator stator windingsearth to 100%.The element measures the residual voltage thirdharmonic component UE3H, due to the non linearityeffect of the magnetic circuit.The operational logic may be programmed as third

harmonic Undervoltage (27H) protection, whenmeasurement is performed by VT or transformer ofthe machine star point, or third harmonic Overvoltage(59H), when measurement is performed using VTwith open triangle secondary on the generator lineside.In both methods, the protective device makes useof a settable (UE3H< for the 27H protective deviceor UE3H> for 59H) and delayed (tUE3H< o tUE3H>)trip threshold with definite time trip characteristic.The device is enabled within the 20...75 Hz frequencyrange.

The element may be associated with the breakerfailure (BF) function.The protective element logical block may beprogrammed using a logical input in order to avoidtripping when the generator is shutting down.Alternatively, inhibition of the protective element withthe generator stopped may be obtained byprogramming a Undervoltage supervision: in thiscase, the 100% stator ground protective function isinhibited when all three phase to phase voltagesmeasured by the line VT fall below an adjustablethreshold (U IN-3H< ).Inhibition of the protective function may also beprogrammed when all three phase currents dropbelow an adjustable threshold (I IN-3H< ), to preventtripping with reduced load generators and any thirdharmonic voltage. This inhibition is deactivated bytripping of the CT monitoring function (74CT).

Active directional overpower (32)The Directional power function may be used to initiatecontrol actions when the generator supplies activepower in excess of a preset limit. For example, someof the actions include shedding excess load orseparation of the generating system due to noise orfaults on the networkThe protective function makes use of a settable(P+>) and delayed (tP+>) trip threshold with definitetime characteristics, enabled for the 20...75 Hzfrequency range.The protective function may be associated with thebreaker failure (BF) function.Logical block of the function may be programmedfrom a binary input.

t

U E3H<

tUE3H<

U E3Ht

U E3H>

tUE3H>

U E3H

t

UU<< U<

t U<<

tU<

27H

59N

0%

10%

50% 100%

30%

Neut

ral v

olta

ge

term

inal

end

vol

tage

3rd component

Fundamental component

Stator earth fault protection (27H)

NTG - Sheet-07-2006 13

Active reverse power (32R)The function measures the three-phase active powersupplied to the generator from the electric networkand/or from other generators operating in parallel.A typical application is as protection against faultsin the prime mover.For generator steam turbines, dragging causesoverheating of the vanes, for hydraulic turbines, thereis increased cavitation of the blades, for diesel motors,there may be explosions of fuel. In such cases, thelevels of active power absorbed by the generatorcompensate for losses of mechanical power resultingfrom dragging of the prime mover (friction, ventilation),hence depends on the type of prime mover.The function makes use of two trip thresholds with settable (P->,P->>) and delayed (t P->,tP->>)definite time trip characteristics.The first threshold can be used when the primemover is dragged; the wide setting range allows usewith any type of prime mover (steam, hydraulic orgas turbines, diesel).For diesel motors, a fault of this type may producean active power exchanged cyclically between thegenerator coupled to the mover and the network toavoid the protective device resetting prior to reachingthe set trip time, and hence without tripping, thereis an adjustable trip time (tP-RES).With the aim of avoiding overspeeding of the unit,which might occur due to the presence of steam inthe turbine following the opening of the machinebreaker at the same time as the closure of the turbineinlet valve, the second threshold may be used in a

sequential tripping logic for opening the machineand field breaker only after closure of the turbineinlet valve.CB open command is issued only if the element istripped and a binary input, configured with sequentialtrip function is actived; the binary input which mustbe activated by a switch when the inlet valve closes. The sequential trip logic must be used when delayedprotection trip whereby the fault or anomalous functionmay be tolerated for a sufficient amount of time sothat, following closure of the turbine inlet, the energyfrom the residual steam looses its mechanical powerto the turbine and the 32R function detects theinversion of generator active power flux.The Reverse power function is enabled within the20...75 Hz frequency range.

The 32R element may be associated with the breakerfailure (BF) function.Furthermore, the logical block of the function, whichmay be used to avoid tripping due to the effect ofcyclical exchanges of active power between thegenerator and the network in the momentssubsequent to synchronisation, may be programmedby a binary input.

Low forward power (37P)The underpower function detects the reduction inthree-phase active power provided by the generatorbelow an adjustable threshold. The Underpower37P function is frequently used for single generatorsoperating in island mode in a sequential trippinglogic for opening the machine and field breaker onlyfollowing closure of the turbine inlet valve, with theaim of avoiding overspeeding of the unit.A further application is the protection againstcavitation of the blades in the pump stations whenthe generator is working as a motor.The 37P function can be actived by means a bankswitching when the generator starts working as amotor.The function makes use of a trip threshold withsettable (P+<) and delayed (tP+<) time independenttripping characteristics.The function is enabled within the 20...75 Hzfrequency range and is blocked by activation of theVT (74VT) or CT (74CT) monitoring functions.The protective function may be associated with thebreaker failure (BF) function.

Furthermore, the function logical block may beprogrammed using a binary input in order to avoidtripping the function when the generator is shuttingdown.

Loss of field (40)Many causes might result in a synchronous generatorlosing excitation: faults with the exciter or its supplysystem, unwanted opening of the field breaker,interruption or short-circuiting of the field winding,brush faults.Under such conditions, the generator’s EMF is clearedthe active power supplied is reduced, the speed ofthe unit increases and the machine then operatesas an asynchronous generator absorbing reactivepower from the network. At speeds exceeding the

synchronism value, flow is established which induceslow frequency currents in the rotor magnetic circuit,in the field windings and dampers, thus resulting inan increase in temperature.With generators with salient poles, the flow reachedin a stable operating state is modest, whereby thegenerator can remain in such a state for long periodsof time without becoming damaged. Instead, withsmooth rotor generators, the level of flow can reachsuch values that the reactive current provided by thenetwork to the generator assumes values even twicethat of the nominal current, with values proportionalto the load initially applied to the generator prior tothe loss of excitation.If the network to which the generator is connectedis not capable of making up the power required bythe generator operating asynchronously (largegenerators connected to a modest short circuit powernetwork), there is a significant reduction in voltageand the system becomes unstable. Under suchconditions, the generator must be quicklydisconnected from the network.Protection against loss of excitation is obtained usinga Underimpedance function with a settable (angleain the clockwise direction with respect to the R axis)and delayed (t AL constant power factor alarmthreshold) two definite time trip thresholds, withcircular trip characteristics in the R-X plane.The diameter (XD1, XD2), the offset along the axisof the abscissa (XO1, XO2) and the trip time (t1<,t 2<) are independently adjustable. The alarmthreshold is used to indicate loss of excitation withlow flow (e.g. generators with salient poles), at whichthe generator remains stably with low levels of activepower distributed and reactive power absorbed andwhich can be tolerated for sufficiently long time.This threshold must be adjusted so as not to trip anyalarms during regular operation of the generator.The first trip threshold, relating to the outer circle,is used to disconnect the generator when loss ofexcitation occurs with low initial load; the diameterof the circle and the relevant trip time must beadjusted so as to avoid the tripping during stablepower swings resulting from the elimination ofnetwork faults or the synchronisation of the unit.Instead, when the loss of excitation occurs with ahigh initial load, whereby the system becomes highlyunstable, the generator is quickly disconnected bymeans of the second trip threshold.The two protective element pickups with circularcharacteristics, together with an adjustable resetdelay (tRES), may also be used as simplified protectionagainst the loss of step for small generators connectedto network with high short-circuit impedance; inparticular, such protection is achieved by adjustingthe reset delay to a value greater than the time withwhich the impedance outputs cyclically from thecircle. When the reset delay is used for this purpose,the trip time must be appropriately delayed so as toavoid tripping the device during stable power swings.A minimum enabling voltage with adjustable thresholdUSUP< may be selected for all thresholds in orderto avoid any unwanted alarms or operation of thedevice when the machine is operating as asynchronous condenser in over-excitation (as withgenerators with hydraulic turbines) or when thegenerator absorbs reactive power from thetransmission lines capacitance connected to thegenerator without any load. The Undervoltage flagenables the three protective device thresholds whenall three voltages together drop below the thresholdUSUP<, otherwise the three thresholds are disabled.

t

TRIP32

PP+>

Q

TRIP32R

TRIP37P

0P-> P+<

P+>P+<P-> 0

t P - >t P+>

t P+<

NTG - Sheet-07-2006 14

To ensure reliable operation, the device is enabledwithin the 20...75 Hz frequency range, if the voltagemeasured exceeds 10%UN and if the current exceeds5% IN.

The three thresholds are blocked upon activation ofthe VT monitoring function (74VT).Tripping of the first threshold may be inhibited bytripping of the second threshold, while the alarmthreshold is always inhibited by tripping of the firstor second thresholds.Each of the two trip thresholds may be associatedwith the breaker failure (BF) function.The logical block for each of the three thresholdsmay be programmed from a binary input.

Negative sequence overcurrent (46)Unbalanced load are due to single-phase or non-linear loads, the tripping of fuses, line interruption inone phase, asymmetric faults, tripping and unipolarreclosing on the transmission lines. The unbalancedload creates a stator magnetic reverse field, whichact on the rotor at double frequency. Hence, currentsare induced at twice the frequency in the rotormagnetic circuit (parasitic currents), the field windingsand the damper windings, responsible for increasedloss of iron and copper and hence overheating of thegenerator.The unbalanced load protective function evalutes thenegative sequence current I2 from the phase currentmeasurements: it makes use of an a settable (I2AL>)and delayed (t2AL>) time independent alarm thresholdand a thermal trip threshold with constant I 22tcharacteristics, developed to optimally coordinatewith the inverse sequence current permissible limitsof generator.The thermal characteristic of the protective elementis defined by means of the following:

t=Kheat/(I2/IB)2where:- t = trip time, measured from the point of exceedingthe adjustable threshold I2>>,- Kheat = thermal time constant of the generator atthe inverse sequence current,- IB = the base current.When the negative sequence current I2 drops below

the threshold I2>>, the protective device resets aftera delay:

Kcool /(I 2>>/IB)2

where the cooling time constant Kcool, representingof the generator at the negative sequence current,is adjustable. This way, the device makes use of amemory which allows the integration of subsequentperiods of excess and relapse of the trip thresholdprior to reaching the trip time. In addition, themaximum (t2MAX) and minimum (t2MIN) time limitsfor the thermal guard are adjustable.The tripping of the maximum inverse sequencecurrent thermal function inhibits that of the relatedalarm threshold.

The trip threshold timer may be reset by using akeyboard command or serial message or a binaryinput if configured for that role.The alarm and trip thresholds are enabled within the20...75 Hz frequency range and are blocked byactivation of the CT supervision function (74CT).The trip threshold may be associated with the breakerfailure (BF) function.The logical block for each of the two thresholds maybe programmed from a logical input.

Stator thermal image (49)This is of the total memory type, with an alarm andtrip threshold.The thermal image protection device is used to protectagainst overheating of the stator windings as aconsequence of genera tor over loading.The element uses the measurement of three statorcurrents in an algorithm reproducing both the heatingproduced by losses due to the Joule effect in thestator windings, and the cooling of the generatorfollowing reduction of the load or its disconnectionfrom the network The algorithm is of the total memorytype, i.e. the actual thermal state also depends onthe heating and cooling cycles previously undergoneby the protected unit. In addition, the equivalentthermal current considered in the calculation of thethermal image considers both the heating producedby the direct sequence current component and thatof the inverse sequence current, according to theequation: I th= w (I 12+k2I 22) with settable k2.

The protective device makes use of a settable alarmthreshold and a trip threshold equal to 120% of thenominal over-temperature, corresponding to anequivalent thermal current of 110% of the basecurrent.Settings are available relating to the heating (t+)and cooling (t-) thermal time constants, in orderto reproduce the generator’s thermal behaviour.Thermal overload protective element may be inhibitby the tripping of at least one of the three overcurrentprotective device thresholds (50/51).application of the relay auxiliary supply voltage orthe Thermal overload initialisation command froman operator via serial communication or a binaryinput, the machine over-temperature is initialised,at a value adjustable by the operator.trip thresholds are enabled within the 20...75 Hzfrequency range and are blocked by activation ofthe CT monitoring function (74CT).The device trip threshold may be associated withthe breaker failure (BF) function.The logical block and/or blocking by logic selectivityfor each of the two thresholds may be programmedfrom a binary input.

t

I th1,1IB

t

t2AL>

I 2

t2MAX

t2MIN

I2AL> I2>>

XO1

XO2

XD2

XD1

0

X

R

NO TRIP

TRIP

TRIP

NO TRIP NO TRIP

ALARM

NTG - Sheet-07-2006 15

&

U L1£U UE<

U L3£U UE<

U L2£U UE<

&

&

CB OPEN

t UE

TRIP 50+27

VT SUPERVISION

t UE-RES

1) GENERATOR SIDE VTs2) NTWORK SIDE VTs

1)

2)

&

Residual overcurrent (50G/51G) / Restricted earthfault (87N)The residual overcurrent protective element 50G/51Gis used to protect against earth faults in the statoror outer windings, for generators with neutralconnected to ground through an impedance. Typically,up to around 90% of the stator windings are protected,starting from the generator line terminals (90% statorground). For the protection of the remaining 10%of the windings near the star point, 100% statorground protection, discussed previously (27H-59H),must be used in combination with 90% stator ground(50G/51G) protection.Measurement of residual current may be performedon phase CT return or by using an summing corebalance transformer; the latter is preferred in orderto obtain greater sensitivity of the protective device. When the system neutral is grounded on the generatorstar point, positioning the phase CT or the summingcore balance transformer on the star point side ofthe machine (or on the neutral ground in the case ofa CT) is preferred, so that protection of the machineis achieved even with the machine CB open.If, neutral grounding is through a special transformeror zigzag reactance on the line or on the busbar, thephase CT or the summing core balance transformermust be positioned on the line side of the generatoritself.Alternatively, by connecting the branch measurementcurrent input to the same CT secondary circuitmeasuring the residual current on the generator lineside and star point, it is possible to use the sameprotective device as a high impedance restrictedearth fault 87N to selectively clear all ground faultswithin the single area delimited by the measurementCT. This protective element, which requires a suitablestabilisation resistor and possibly a non-linearMETROSIL resistor in order to limit over-voltages inthe secondary circuit in case of internal faults, isuseful when several generators are connected inparallel on the same busbar, so as to disconnect onlythe generator with the stator ground fault.With only the residual current’s fundamentalcomponent being measured, the protective elementis insensitive to third harmonic and higher ordercomponents.

The protective element has three independentlysettable (IE>, IE>>, IE>>>) and delayed (tE>, tE>>,t E>>>) trip thresholds, of which the first isprogrammable with definite-time or inverse tripcharacteristics in accordance with the inverse, veryinverse, extremely inverse time IEC curves (A,B,C),

Phase overcurrent (50/51)The overcurrent protective element is used to protectagainst multiphase short-circuits for small generatorsor as a back-up to differential protection (87G), toUnderimpedance (21) or to Voltage-controlledovercurrent protection (51V) for greater generators.The protective element is tripolar, with threeindependently settable (I>, I>>, I>>>) and delayed(t>, t>>, t>>>) trip thresholds, of which the first isprogrammable with definite-time or inverse tripcharacteristics according to inverse, very inverse,extremely inverse time IEC curves (A,B,C), or withconstant I2t, the second threshold having definite-time or inverse characteristics with constant I2t,while the third threshold has definite-timecharacteristic.Current measurement may be performed with phaseCT located on the generator star point side or lineside, but location on the star point side is to bepreferred so that protection of the unit is achievedeven with the machine circuit breaker open.

There is an adjustable reset time, common to allthree protection thresholds (t IRES) and usable forcoordination with electromechanical relays, in orderto sensitise the device against swings between thegenerator and the network or to reduce intermittentfault elimination times.Inhibition of tripping of the first threshold I> may be

selected by the tripping of at least one of the twothresholds (I>>, I>>>). Analogously, inhibition oftripping of the second threshold I>> may be selectedby tripping of the third threshold I>>>.The thresholds are enabled within the 20...75 Hzfrequency range.Each of the three thresholds may be associated withthe breaker failure (BF) function.The logical block and/or blocking by logic selectivitymay be selected for each of the three thresholds.

Inadvertent energization (50+27)Connection of a standing (or non-yet synchronized)generator to the network following fast actuation ofthe circuit breaker is the cause of severe damage tothe machinery; under such conditions, it operates asan asynchronous machine with high flow values,hence with high currents induced in the rotor, causingvery rapid overheating.The protective element consists of a Overcurrentenabled by the condition of the standing machineafter an adjustable time tUE.The logic relating to the standing machinery dependson the positioning of the VT used to measure thevoltages, whether on the generator side, or networkside with respect to the mains breaker.With "GENERATOR SIDE VT" set-up, the condition ofthe standing machine is detected when all threephase voltages are less than the adjustable thresholdUUE<, in the absence of tripping of the VT monitoringfunction (74VT) and when the machine breaker isopen.Instead, with "NETWORK SIDE VT" set-up, thecondition of the standing machine is detected whenall three phase voltages are less than the adjustablethreshold UUE<, and in the absence of tripping ofthe VT monitoring function (74VT) and when themachine breaker is open.Following closure of the mains breaker, tripping ofthe protective element occurs instantaneously whenat least one of the adjustable Overcurrent thresholdphase currents IUE< is exceeded, while ability is stillmaintained for an adjustable time tUE-RES.The status of the machine breaker is associated witha relay binary input.The protective device may be associated with thebreaker failure (BF) function.

Logical block of the device may be programmedfrom a binary input. t

I EI E>

t E>

t E>>>

t E>>

I E>> I E>>>

t

II>

t >

t>>>

t>>

I>> I>>>

Inadvertent energization (50+27)

NTG - Sheet-07-2006 16

the second and third thresholds having definite-timecharacteristics. Inhibition of tripping of the firstthreshold IE> may be selected by the tripping of atleast one of the two thresholds I E>>, I E>>>.Analogously, inhibition of tripping of the secondthreshold IE>> may be selected by tripping of thethird threshold IE>>>.A reset time may be set, common to all threethresholds of the protective device t IERES), whichmay be used for coordinat ion with theelectromechanical relays and to reduce theintermittent fault elimination time.The thresholds are enabled within the 20...75 Hzfrequency range.Each of the three thresholds may be associated withthe breaker failure (BF) function.The logical block and/or blocking by logic selectivitymay be selected for each of the three thresholds.

Voltage controlled/restrained overcurrent (51V)As an alternative to the Underimpedance protectiveelement (21) the Voltage-controlled current protectivedevice may be activated to protect the generatoragainst short-circuiting between the phases outwiththe area of the differential protective device 87G andas a back-up to the latter. The voltage dependenceof the protective device 51V allows detection of thegenerator short-circuit current even when thereduction is such that values less than the nominalcurrent are reached, as in the case of generatorswith excitation derived from terminals or, in the caseof excitation by a separate supply, but with voltageregulator faults.Current measurement may be performed with phaseCT located on the generator star point side or lineside, but location on the star point side is to bepreferred so that protection of the machinery isachieved even with the machine breaker open. Thevoltage-dependent Overcurrent protective functionhas two independently adjustable trip thresholds,both time independent deferrable.The current-voltage trip characteristics of theprotective element may be selected from two types:- voltage restrained, where the current thresholdof the protective element is switched from anadjustable value corresponding to load operation(I I/U> for the first threshold, I I/U>> for the secondthreshold) to a lower value corresponding to short-circuit (KI I/U> for the first threshold, KI I/U>> for thesecond threshold with adjustable reduction factor Kcommon to both thresholds), when the voltage dropsbelow an adjustable threshold (U I/U< common tothe first and second thresholds).The corresponding trip times (t I/U>, t I/U>>) may be

First threshold U> tripping may be inhibited bysecond threshold U>> tripping.The device is enabled within the 20..80 Hz frequencyrange. Each of the two thresholds may be associatedwith the breaker failure (BF) function. The logicalblock for each of the two thresholds may beprogrammed from a logical input.

Residual overvoltage (59N)The residual overvoltage protective element is usedto protect against earth faults in the stator or outerwindings, for underground generators or connectedto ground through a high impedance. Typically, upto around 90% of the stator windings are protected,starting from the generator line terminals. For theprotection of the remaining 10% of the windingsnear the star point, 100% stator ground protection,discussed previously (27H-59H), must be used incombination with 90% stator ground (59N) protection.Measurement of residual voltage may be carried outby VT with open triangle secondary positioned on thegenerator line side, or by VT or transformer insertedbetween the generator star point and ground. WhenVT is used on the line side, it is preferable that thisbe positioned between the generator and the relevantCB, so that the generator itself is protected, evenwith the CB open. With only the residual voltage’sfundamental component being measured, the Neutralovervoltage protective device is insensitive to thirdharmonic and higher order components.There are two independently settable (UE>, UE>>)and delayed (tUE> and tUE>>) thresholds, of whichthe first has programmable definite-time or inverse-time trip characteristics, whilst the second is timeindependent.

adjusted for each of the two thresholds. The restrainvoltage element is used when the generators isdirectly connected to the electric network.- voltage-controlled, whereby, for the first threshold,if the voltage exceeds the threshold U I/U-1< thenthe adjustable current threshold I I/U>is enabled, ifthe voltage is less than the threshold U I/U-2< thenthe threshold KI I/U> with adjustable reduction factorK is enabled, whilst if the voltage lies between thethresholds U I/U-2< and U I/U-1<< then the currentthreshold varies between the values I I/U> and KI I/U>in proportion to the voltage measured. For the secondthreshold, the operating logic is analogous to that ofthe first threshold and the current threshold II/U>>with the relevant reduction KI I/U>> are adjustable. The voltage threshold U I/U-1< , U I/U-2< andreduction factor K adjustments are common to thefirst and second thresholds.

The corresponding trip times (t I/U>, t I/U>>) may beadjusted for each of the two thresholds.

The voltage-controlled element is used when thegenerator is connected to a step-up transformer.There is an adjustable reset time, common to bothprotection thresholds (t IURES) and usable forcoordination with electromechanical relays, in orderto sensitise the device against swings between thegenerator and the grid, or to reduce intermittent faultelimination times. The protective element 51V isenabled with voltages exceeding 1% UN and withcurrents exceeding 5% IN. Inhibition of tripping ofthe first threshold (I I/U>, KI I/U>) may be selectedby tripping of the second threshold (I I/U>>, KI I/U>>).The thresholds are enabled within the 20...75 Hzfrequency range and are blocked upon activation ofthe VT monitoring function (74VT). Each thresholdmay be associated with the breaker failure (BF)function. The logical block and/or blocking by logicselectivity may be selected for each threshold.

Overvoltage (59)The overvoltage function is typically used as aprotective device to prevent damage to the generatorinsulation or to loads in the case of any increases involtage due to faults with the automatic voltageregulator or erroneous operations with manual voltageadjustments. Three phase measurement of the phasevoltages or the phase to phase voltages may beselected, just as with the protection device operatinglogic ("AND" or "OR" of the three voltages). Thereare two independently settable (U>, U>>) and delayed(tU> and tU>>) thresholds, of which the first hasprogrammable definite-time or inverse-time tripcharacteristics, whilst the second is time independent.

t

UU >

tU>

t U>>

U>>

t

U EU E>

t UE

t UE>>

U E>>

Current pickup

Phase to phasevoltage

U I/U-2<

I I /U>

U I/U-1<

KI I /U>

51V Voltage Controlled characteristic

Current pickup

Phase to phasevoltage

U I/U<

I I /U>

KI I /U>

51V Voltage Restraint characterist ic

NTG - Sheet-07-2006 17

First threshold UE> tripping may be inhibited bysecond threshold UE>> tripping.A reset time may be set, common to both thresholdsof the protective device (tUERES), which may beused for coordination with the electromechanicalrelays and to reduce the intermittent fault eliminationtime.The device is enabled within the 20... 80 Hz frequencyrange. Each of the two thresholds may be associatedwith the breaker failure (BF) function. The logicalblock for each of the two thresholds may beprogrammed from a logical input.

Rotor earth fault (64F)The field circuit has no ground connections, wherebythe generator may continue operation even with aground fault. A ground fault however, increases theprobability of a second ground fault somewhere else,with which there would be unbalances in the rotorflux, with consequent vibrations in the bearings andthe shaft of the machine. A rotor ground protectiveelement is available, having the aim of anticipatingdamage to the generator by detecting the first earthfault in the field circuit. Such protection may be usedon alternator excitation circuits with capacitance toground of up to 2 mF and static exciters havingnominal voltages up to 660 Vdc. Measurement usesa 50 Hz signal applied to the generator field circuit. There is no circulation of any current due to theapplication of the 50 Hz signal until the field circuitloses insulation. Instead, in the case of the firstground fault, there is the circulation of a current at50 Hz, which the NTG measures as the sole resistivecomponent in order to determine the resistance ofthe circuit insulation to ground, calculated as theratio between the voltage applied at 50 Hz and thecorresponding resistive component of the current.The reduction in the resistance measured by therelay indicates a first loss of field circuit insulation. The relay must be connected to both positive andnegative poles of the field circuit with the aim ofreducing the influence of harmonics in themeasurement; in the case of inaccessibility to oneof the two poles, then connection may in any casebe made to the sole accessible pole. An appropriatefilter allows attenuation of the harmonics generatedby the static exciters to 150 and 300 Hz. The voltageapplied at 50 Hz, the filter for attenuation of theharmonics and the resistances for coupling to thefield circuit are housed within the same casing ofthe NTG relay. To generate the voltage applied to

the field circuit, there is a specific auxiliary supplyinput at 50 Hz, independent from the NTG relayauxiliary voltage input. The insulation resistancemeasured is compared with two adjustable thresholds,of which the first anticipates the alarm (RFAL<) andthe second tripping (RF<<); in addition, each thresholdis independently delayed (tRFAL<, tRF<<). Trippingof the second threshold inhibits the first alarmthreshold. Each of the two thresholds may beassociated with the breaker fault (BF) function.The logical block for each of the two thresholds maybe programmed from a binary input.

Overfrequency (81O)Increasing of the frequency beyond the nominal valueis a consequence of excess mechanical power appliedto the generator with respect to the active power ofthe load. The most common cause of increasingfrequency is a substantial shedding of load, to whichthe unit speed regulator, following a transient eventresulting from the reduction of input to the primemover, responds in order to restore the frequency tothe nominal value.The Overfrequency protective element is used as a

back-up in the case of speed regulator faults duringa loss of load, anticipating mechanical damage tothe turbine-alternator unit and avoiding supplyingloads with frequencies beyond the preset limits. Forthe coordination with the speed regulator, theprotective device makes use of two independentlysettable (f>, f>>) and delayed (t f>, t f>>) tripthresholds with definite-time characteristics.

Frequency measurement is enabled only if the voltageexceeds 10% UN. The protective device is enabledwithin the 20...75 Hz frequency range.Inhibition of tripping of the first threshold may beselected by tripping of the second threshold. Eachof the two thresholds may be associated with thebreaker failure function. The logical block for eachof the two thresholds may be programmed from abinary input.

Underfrequency (81U)The drop in frequency with respect to the nominalvalue is the consequence of the reduction of activepower provided by the generator with respect to themechanical power applied. The drop in frequencyoccurs during the switching of the generator tooperation in isolation, when it becomes separatedfrom the electricity network and a load greater thanthe power generated is left connected to the generatoritself (or to several generators). In such cases, thefrequency may only be restored to the nominal valueby the loads shedding. Operation at reducedfrequency is critical above all for the prime movercoupled to the generator, especially for steam turbinesdue to the mechanical resonance of the blades. TheUnderfrequency function may hence be used in orderto initiate detachment of local loads or as back-upprotection for the detachment of the generator incase load shedding is unsuccessful. For loadshedding, the Underfrequency function makes useof four independently settable (f<, f<<, f<<<, f<<<<)

and delayed (t f<, t f<<, t f<<<, t f<<<<) tripthresholds. Frequency measurement is only enabledif the voltage exceeds 10% UN. The element isenabled within the 20...75 Hz frequency range.The following may be selected:- Inhibition of tripping of the third threshold by trippingof the fourth threshold,- Inhibition of tripping of the second threshold bytripping of the third or fourth threshold,- Inhibition of tripping of the first threshold by trippingof the second or third or fourth threshold.Each of the four thresholds may be associated withthe breaker failure function.For each of the four thresholds, the logical block maybe programmed from a binaryinput, for example inorder to avoid shedding loads during generator shut-down.

t

ff<<<<

t f<<<<

f<<<

t f<<<

t f<<

t f<

t

ff >

t f>

t f>>

f>>

t

R F<

t RFAL<

t RF<

R FAL<NTG

IF

UF

L+

L-GS

f<< f<

NTG - Sheet-07-2006 18

Breaker failure (BF)If tripping of a protective device controlling theopening of the circuit breaker should occur, due toany faults or anomalous operation of the generator,but, in case of a tripping failure of the circuit breaker,then the breaker failure BF function issues a back-up command to trip an higher level circuit breaker.The breaker failure protective device may be activatedby the tripping of NTG relay internal protectivefunctions, also associated with the BF device, or thetripping of external protective devices (for examplethe generator differential protective device 87G)connected to an NTG relay logical input.The contition for starting of the BF function andtripping of protections depend on the phase CTsposition.

If they are connected on the star side of the generator(preferred to guarantee protection for internal faultsthrough 21-51v/46 functions), the BF element isinitiated by the closed condition of the mains CB (52aand 52b checking by means binary inputs).

If the CTs are connected on the line side of thegenerator (ie, when star terminals are unavailable),,the BF element is initiated by the closed conditionof the mains CB or if at least one of the three phasecurrent or the residual current exceeds thecorresponding adjustable threshold (IBF>, IEBF>). Checking the breaker status or the presence ofcurrents improves the reliability of the breaker failureprotective device, making its tripping possible evenin the absence of any current (for example, by trippingof the frequency, voltage and Overexcitation protectivedevices) or with auxiliary contact states inconsistentwith the status of the breaker.With CTs connected on the star side of the generatorthe BF element is not initiated by the currentmeasuring criteria (IBF>, IEBF>), to avaid unwanted

trips of the BF function due to the faul internal currentstill present after the CB opening.Breaker failure tripping occurs after an adjustabletime delay tBF, if the device trip conditions and theclosed breaker condition persist for the entire duration

of the tBF time itself.The BF protective element is enabled within the20...75 Hz frequency range.Logical block of the BF protective device may beprogrammed from a binary input.

ANCILLARY FUNCTIONSLine VT supervision (74VT)The line VT supervision function is used to detectNTG relay voltage input anomalies from the line VTs.Anomalies may arise due to interruptions of the VTsecondary connections, due to the tripping of fusesprotecting the VTs or the automatic breaker protectingagainst over-currents on the VT secondary circuit.The function is used, both in order to provide analarm signal and in order to block those NTG relayprotective devices which might erroneously trip inthe absence of any measured voltages.The function detects VT anomalies under the followingconditions:- loss of one or two phase voltages;- loss of the three phase voltages to load;- absence of the three phase voltages followingpower-up.The loss of one or two phase voltages is detectedwhen the inverse sequence voltage exceeds anadjustable threshold (U 2VT>) and the inversesequence current is less than an adjustable threshold(I2VT>).Loss of the three phase voltages to load is detectedwhen the three phase voltages are all less than anadjustable threshold (UVT<) and if all three phasecurrents, at the current cycle, of the network quantitiesdo not differ by an adjustable threshold (DIVT<) fromthe value of the same currents during the precedingcycle.Checking for no variations in current between thepresent and preceding networkperiods, avoidserroneous activation of the 74VT function when athree phase surge short circuit occurs close to VT,

VTs monitoring logic diagram (74VT)

IBF>

TRIP INSIDE PROTECTION

&CB CLOSED

t BF

TRIP EXTERNAL PROTECTION

1

BF BLOCK

B

A

A CT on LINE sideB CT on STAR side

IBF>

IBF>

IEBF>

Breaker failure fogic diagram

&

U L1 £ U VT<

U L3 £ U VT<

U L2 £ U VT<

&

|I L1(k)-I L1(k-1)|£ DI VT<

|I L3(k)-I L3(k-1)|£ DI VT<

|I L2(k)-I L2(k-1)|£ DI VT<

&

&

&

CB CLOSED

t VT-AL ALARM

BLOCK21-51V/27/37/40/50+27

&

& S

RQ

S

RQ

&74VT AUTORESET

RESET BUTTON PUSHED

PC LOCAL RESET COMMAND

REMOTE INTERFACE RESET COMMAND

MCB VT OPEN

&

74VT BLOCK

&

74VT BLOCK ON

NTG - Sheet-07-2006 19

when voltages undergo a drastic reduction andcurrents increase rapidly.Instead, under load conditions, currents will not vary,or in any case, the variation, due to load changes,will be less than that in short-circuiting.While using such logic, in order to avoid the 74VTfunction not being activated following power-up(closing the machine switch) whilst the line VTs aredisconnected, due to the large increase in currentsupplied to the load, this condition is recognised ifthe switch is closed and if the three phase voltagesare all less than the adjustable threshold (UVT<) andthe three phase currents are all less than anadjustable threshold (IVT>), the latter is to be set ata value greater than the current at the powering-upof the load, but less than the short-circuit current.Activation of the 74VT function without any intentionaldelays takes care of the blocking of those protectivedevices which might trip in the absence of anymeasured voltages and, following an adjustable time(tVT-AL>) provides an alarm signal.

Phase CT supervision (74CT)The phase CT supervision function is used to

detect anomalies in the phase CT secondary circuitsor the NTG relay current inputs. Anomalies may arisedue to interruption of the CT secondary connections,causing the tripping of some of the protective functionsas well as dangerous secondary over-voltages of theCTs themselves. The function is used both to providean alarm signal and in order to block those NTG relayprotective devices which might trip erroneously inthe absence of any measured currents. The functiondetects anomalies in the secondary circuits of oneor two phase CTs by checking that the residualcurrent, calculated as the vectorial sum of the threephase currents measured, exceeds an adjustablethreshold (I ECT>) and that the residual voltagemeasured remains less than another adjustablethreshold (UECT<). That avoids activation of the 74CTfunction as a result of earth faults, in the presenceof both residual current and residual voltage.Activation of the 74CT function without any intentionaldelays takes care of the blocking of those protectivedevices which might trip in the absence of anymeasured currents and, following an adjustable time(tCT-AL) provides an alarm signal.

Trip circuit monitoring (74TCS)The trip circuit may be monitored by the NTG relayin order to indicate any anomalies leading to failureof the breaker due to tripping of protective devicesor intentional commands from the operator. The74TCS monitoring function detects anomalies suchas auxiliary voltage interruptions or faults and tripcoil interruptions/short-circuits.Trip circuit monitoring may be achieved by using twoor one NTG relay logical inputs.In the first case, the two logical inputs are connectedin parallel respectively to the protective device tripcontact and to an auxiliary contact normally closedby the switch: an anomalous condition is indicatedby the deactivation of both logical inputs.the second case, the NTG relay logical input isconnected in parallel to the trip contact of theprotective devices and to an auxiliary contact, normallyclosed by the switch and connected in series to ahigh value resistance: an anomalous condition isindicated by the deactivation of the logical input.Monitoring performed using two logical inputs hasthe advantage of being also able to detect mechanicalswitch faults.

Binary input functionsThe independently configurable active high or lowlogical inputs may be used for the following accessoryfunctions:1) Resetting the relay (from a contact associatedwith an independent binary input).2) Switching between the two setting parametersconfiguration (from a contact associated with anindependent binary input).3) Control logging of the values measured at trip/start-up (from a contact associated with an independentlogical input).4) Blocking by logical selectivity (from two contacts,normally open, with block output function, associatedwith two independent binary inputs, separately forOvercurrent and ground functions, or from a startcontact associated with an independent binary inputcommon to the Overcurrent and ground functions).5) Blocking protective functions (from a contactassociated with an independent binary input).6) Supervision of the trip circuit (function indicatedby the initials TCS "Trip Circuit Supervision"), up toone of two binary inputs.7) Control clock synchronisation, through dataconnection to the supervision system (from a contactassociated with an independent binary input).8) Monitoring of the breaker status, with indicationof open, closed or faulty switch to the display, to anLED if configured, over a serial communication lineand SELF-TEST relay for fault indication, withconsistency checking by simultaneous acquisitionof the status of a switch auxiliary contact, normallyopen, and another auxiliary contact normally closed.9) CB open and close control from external keysassociated with logical inputs, if configured.Two binary inputs, associated with a normally openand closed switch auxiliary contact, are used for theabove function; hence the function comprisesmonitoring the status of the switch as indicated in 8.10) Switch diagnostics, with diagnostic mode (tallyof number of openings, cumulative value of thecurrents broken by each pole, cumulative value ofI2t broken by each pole, duration of the opening andclosing operations), relevant alarm thresholds anduser configurable counter reset mode depending onthe switch type and relevant maintenance programme. The same two binary inputs, associated with normallyopen and closed switch auxiliary contacts, are usedfor the above function; in relation to the switch statusmonitoring function as indicated in 8.11) Breaker failure with breaker status monitoring(BF). The same two logical inputs, associated withnormally open and closed switch auxiliary contacts,

are used for the above function; in relation to theswitch status monitoring function as indicated in 8,and a third configurable binary input for detection ofexternal protective device tripping.12) Thermal image initialisation.13) Resetting the number of trips and/or start-upsfor each threshold (from a contact associated withan independent binary input).14) Resetting the number of switch opening operations(from a contact associated with an independentbinary input).15) Resetting the number of switch closing operations(from a contact associated with an independentbinary input).16) Resetting the cumulative value of the currentsbroken by each pole of the switch (from a contactassociated with an independent binary input).17) Resetting the cumulative value of the I2t brokenby each pole of the switch (from a contact associatedwith an independent binary input).18) Resetting the maximum, minimum, fixed meanand movable mean of the quantities (from a contactassociated with an independent binary input).19) SEQUENTIAL TRIPPING for enabling the Reversepower (32P) and Low forward power (37) protectivedevices from a turbine inlet valve contact.20) Resetting the timer counter relating to themaximum inverse sequence current protective device(46) trip threshold.

The following timers, adjustable within the range0.00...100.0 s, with resolution of 0.01 s, within therange 0.00...9.99 s and 0.1 s, within the range10.0...100.0 s are independently associable witheach binary input (one timer for each logical input):- an activation delay timer, start-up of which isbrought about by the activation of the input itself; ifthe end time is reached, the timer trips its own output(high if the corresponding logical binary is set activehigh, or low if the corresponding logical input is setactive low), which remains active until thecorresponding binary input is reset.The timer may be used to delay activation of thefunctions associated with the logical inputs.- a deactivation delay timer, start-up of which isbrought about by the activation of the input itself; ifthe end time is reached, the timer deactivates itsown output (low if the corresponding logical input isset active high, or high if the corresponding logicalinput is set active low).The timer may be used as a back-up in logic selectivityprotection systems against pilot wire short-circuiting.

NTG

CB TC

74TCS

52NA 52NC

PROTECTIONTRIP

Uaux

IN1

IN2

NTG

CB TC

74TCS

52NA 52NC

PROTECTIONTRIP

Uaux

IN1

Logic diagram of Trip circuit supervision (74TCS) with twobinary inputs

Logic diagram of Trip circuit supervision (74TCS) with onebinary input

D1D2D3D4D5D6D7D8D9D10D11D12

C1C2C3C4C5C6C7C8C9C10

C12C11

E7E8

E9E10

E11E12

E1

E2

E3

E4E5

E6

N7N8N9N10

B12

B10

B11

B7

B8

B5

B6

B3

B4

B1

B2

A7

A8

A5

A6

A3

A4

A1

A2

F7F8

F9F10

F11F12

F1

F2

F3

F4F5

F6

N1

N2

L1L2

L3L4L5

L6L7L8

L9L10L11

L12M1M2

M3M4M5

M6M7M8

M9M10M11

M12

G1G2

G3G4G5

G6G7G8

G9G10G11

H1H2

H3H4H5

H6H7H8

H9H10H11

H12

G12

DIG-IN1

DIG-IN2

DIG-IN3

DIG-IN4

DIG-IN5

DIG-IN6

DIG-IN7

DIG-IN8

DIG-IN9

DIG-IN10

DIG-IN11

DIG-IN12

DIG-IN13

DIG-IN14

DIG-IN15

DIG-IN16

RTD1

RTD2

RTD3

RTD4

RTD5

RTD6

RTD7

RTD8

K9

K10

K1

K2

K3

K4

K5

K6

K7

K8

K11

K12

K13

K14

K15

K16

NTG - Sheet-07-2006 20

(1)

I/O CONNECTION FOR PRO CONFIGURATION

NOTE (1)

Connection of the auxiliary

power supply for the 64F

protection function is shown

on page 23

E7E8

E9E10

E11E12

E1

E2

E3

E4E5

E6

B12

B11

B7

B8

B5

B6

B3

B4

B1

B2

A7

A8

A5

A6

A3

A4

A1

A2L1L2

L3L4L5

L6L7L8

L9L10L11

L12M1M2

M3M4M5

M6M7M8

M9M10M11

M12DIG-IN1

DIG-IN2

DIG-IN3

DIG-IN4

DIG-IN5

DIG-IN6

DIG-IN7

DIG-IN8

K1

K2

K3

K4

K5

K6

K7

K8

NTG - Sheet-07-2006 21

I/O CONNECTION FOR BASIC CONFIGURATION

NTG - Sheet-07-2006 22

50G/51G

81U

81O

Generator with starpoint resistor or neutral earthing transformer

NTG - Sheet-07-2006 23

Generator with isolated starpoint and residual voltage measured from starpoint and ground

(1)

(1)

81U

81O

N11

N12

NOTE (1)

Measurement of residual voltage may be carried out by VT withopen triangle secondary positioned on the generator line side

NTG - Sheet-07-2006 24

Generator with isolated starpoint connecetd to busbar or resistance grounding with Zig-Zag transformer or reactance

(1)

(1)

(4)

(4)

(1)

(2)

(3)

81U

81O

N11

N12

NOTE (1)

Only for generator connected in parallel with the electrical

network or other generators

NOTE (2)

Only for impedance grounded starpoint (≥10A).

Residual current must be detected on the line side of generator

NOTE (3)

For busbar or internal ground faults with Circuit Breaker open

NOTE (4)

For internal multi-phase short circuit with CB open.

Current measurement may be performed with phase CTs

located on the star point side

NTG - Sheet-07-2006 25

Parallel connection of generators with earthing resistor

(1)

R3

81U

81O

N11

N12

NOTE To locate faulted generator an external 87G differential protection must be provided

NTG - Sheet-07-2006 26

Isolated generator with step-up transformer

81U

81O

N11

N12

(1)

(1)

(2)

(2)

NOTE (1)

Only for generator connected in parallel with the electrical

network or other generators

NOTE (2)

For internal multi-phase short circuit with CB open.

Current measurement may be performed with phase

CTs located on the star point side

NTG - Sheet-07-2006 27

RTD2

+V

MIS2

RIT2

RTD3

+V

MIS3

RIT3

RTD4

+V

MIS4

RIT4

RTD5

+V

MIS5

RIT5

RTD6

+V

MIS6

RIT6

RTD7

+V

MIS7

RIT7

RTD8

+V

MIS8

RIT78

C1

RTD1

+V

MIS1

RIT1

C2

C3

C4C5

C6

C7C8

C9

C10C11

C12

D1D2

D3

D4D5

D6

D7D8

D9

D10D11

D12

RTD probes

NOTERT1...RT8 terminals are internally connected to chassis

ground

NTG - Sheet-07-2006 28

DIMENSIONS

COMMUNICATION

ANCILLARY FUNCTIONS

HARDWARE

NTG - Sheet-07-2006 29

NTG Equipment

Undervoltage (27)

Reverse power (32R)

Loss of field (40)

Negative sequence overcurrent (46)

Thermal image (49)

Overcurrent (50/51)

Earth fault (50G/51G)/Restricted earth fault (87N)

Underimpedance/Voltage controlled overcurrent (21-51V)

Phase overvoltage (59)

Residual overvoltage (59N)

Overfrequency (81O)

Underfrequency (81U)

100% stator earth-fault with 3rd harmonic:residual under-overvoltage (27H-59H)

Directional active overpower (32)

Active underpower (37P)

Inadvertent energization (50-27)

Overexcitation (24)

Thermal with n° 8 termometric probe inputs (26)Rotor earth fault (64F)

Breaker failure (BF)

VT supervision (74VT)

CT supervision (74CT)

Trip circuit supervision (74TCS)

CB self-test

Multiple setpoint profiles

Logic selectivity

Sequential trip

Event logging

Measuring recorder

Self diagnostic

N° 8 digital inputs + N° 8 outputl relays + N° 16 indicator LEDs

N° 16 digital inputs + N° 16 output relays + N° 24 indicator LEDs

TX communication module (copper RJ45)

FX communication module (optical fiber)

Auxiliary power supply 48…110VAC/DC

Auxiliary power supply 24 AC/DC

Auxiliary power supply 230 AC ( By means DAC200 adapter)

1/5 A Nominal current selectable with jumper settings

Modbus TCP/IP (communication module required)

STANDARD

OPTIONAL

NOT AVAILABLE

PROTECTION FUNCTIONS BASIC PRO

Headquarters: 20139 Milano - Piazza Mistral, 7Tel. +39 02 574 957 01 ra - Fax. +39 02 574 037 63

Factory: 35127 Padova - Z.I. Sud - Via dell’Artigianato, 48Tel. +39 049 894 770 1 ra - Fax. +39 049 870 139 0

e-mail: thytronic@thytronic.itweb: www.thytronic.it