Gustavo Forster RED 670 Line Differential ABB …ceb5.cepel.br/arquivos/artigos_e_documentos/prot_dif/abb.pdfRED 670 Line Differential Protection Terminal Gustavo Forster [email protected]

© S

EP

TU

A/T

TP

S -

1 -

2004-0

4--

28 -

RE

L 5

71 1

.0.p

pt

RED 670Line Differential

Protection Terminal

Gustavo [email protected]

ABB Substation Automation Systems

Brazil

www.abb.com/substationautomation

Bertil Lundqvist 2005-09-07, slide 2

Features: RED670

Line differential terminal for:

All voltage levels

OH-lines

Cables

Double circuit lines

Series compensated lines

Single and two pole tripping

Optional protection functions

Digital communication between line ends

Route switched communication networks

Easy upgrading from 2 terminal to tapped line protection


Line Differential Protection: RED670

Application Areas

Multi-terminal lines with communication to 4 remote line ends

Multi-terminal lines with transformers in the protected zone

Tapped lines

Tapped lines with transformers

Short lines

Long lines with charging current compensation


PS

M

Remote communication module with 4 ports

Digital communication channels, 64 kbit/s, are required

Possibility for redundant channels (for 2 to 3 terminals)

Fibre optical module for dedicated fibres

C37.94 optical module

External G.703 converter (optical/electrical)

Two local analogue inputs for differential protection

Additional local inputs for complementary protection

Hardware Structure

CB3

CB2

CB1

No external summation

NU

M

IOM

BO

M PS

M

TR

M1

GS

M

AD

1

BIM

MIM

BIM


> <

RED670

><

RED

670

External

Modem

21-216

PCM><

Optical/galvanic modem C37.94 protocol from RED 670G703 64 kbit or G703E1 2 Mbit from modem to PCM

< 10 m

Back-to-backC37.94 protocol

G703

Optical fibres

Three Communication Alternatives

RED

670PCM>

< C37.94 protocol from RED 670

Route switched systemsPCM with C37.94 interface

RED670

Optical fibres

Optical fibres


Route switched systems with REL 551/561

Tolerates different routes in forwardand reverse direction only during switching

< 0,2-0,5 ms difference continuous*

Maximum transmission time∆T < 15 ms

B

A C

*Depending on required sensitivity

EC

REL551/561

EC

REL551/561


GPS system required for set up

GPS loss tolerated with:

Free-wheeling internal clocks

Fall back to the echo method

Maximum transmission timeTd < 40 ms

GPSclock

D

B

A C

GPSclock

GPSclock

GPSclock

Route switched systems with RED 670

Tolerates unspecified route

switching in telecommunication

systems (SDH/PDH)


Excellent tripping time <25 ms

Completely phase segregated measurement

Extremely stable for external faults

Very good sensitivity for internal faults

Flexible communication configuration - back-to back systems

- route switched systems with fixed transmission time in both directions using echo-synchronisation

- telecommunication (SDH) systems with undefined route-switching using GPS synchronisation

Multifunction configuration

Main features for the differential protection


Low CT requirements,

Allowed CT ratio difference < 30:1

Differential algorithm not dependent on the number of connected lines

Dual slope stabilisation

Minimum operate current 10-150%

Transfer trip can be sent to all terminals

Main features


bias

Idiff

Normal condition

ΙΙΙΙ

Imin

Dual slope stabilisation


Fourier coefficient

Iphase = f(t) = f(ωωωωf) + f(ω≠ωω≠ωω≠ωω≠ωf)

f(ωωωωf) = a*sin ωωωωf t + b*cos ωωωωf t

a and b transmitted and evaluated

• Minimum transmission demand

• Maximum security

• Reduced influence from charging currents

• a and b transmitted every 5 ms

REL 551/561 Current information


Evaluation every 5 ms

Trip at 2 or 3 “trip”evaluations out of 4 evaluations

a and b are transmitted together with check bits

”Moving

Window”

2/3 of 45 ms

T T 00 0 0 0 T 0 0 0 0 0

REL 551/561Trip Evaluation Logic


RED 670 Differential protection principle

Time taggedinstantaneoussampled values

Remote Communication

Local anlogueinputs

All currents iin , iout & id are calculated from phase current values from all line ends

DifferentialProtection algorithm

ioutiin

id

Line end A2Line end A1

Line end BLine end CLine end DLine end E Σ I= O +

charging current


Time taggedinstantaneoussampled phase currents values

RED 670 Differential protection principle

Symmetricalcomponents

Fourierfilter

Remote Communication

Local anlogueinputs

Transformer inrush blocking- second harmonic- wave block- 5 th harmonic

Transformerinterturn fault-negative sequence2-20% of I base

Currentdifferential

BlockTripBlock

StartTrip

onoff


Sampled values collected every 1 ms

Communication message sent every 5 ms

Each communication message contains 5 sets of sampled values

RED 670 Differential Trip Security

5 ms

0 T 00 0 0 0 0 0 T 0 0 0

Trip enabled with 5 consecutive sample sets calculated to trip

1 or 2 messages required depending on fault incidence point

12345

12

345


CT-Saturation Detector

CT-saturationdetected

Ι <K1dΙ

dt<K2 Ι-t >K3

-t

• Security at external fault

• Minimum CT requirement


Charging Current

RED

670

RED

670

Communication

Ic1

Ic2I

diff,false = I

c1 + I

c2


Charging Current Compensation

Continuous estimation of differential current at no-fault condition: Charging current

Pre-fault charging current estimation kept during faults

Subtraction of the false pre-fault differential currents

At low resistance faults the fault current is large: dominating over the charging current: Error in the charging current compensation has minor influence

At high resistive faults the voltage is maintained and the charging current is close to the non-faulted case


Power transformers can be applied within the protected zone

Small power transformers without a line differential terminal

Time delayed differential function gives selective tripping for secondary side faults

Instantaneous differential function for faults on the line

Id> Id >

Id >

Id> Id >

Application examples


CB 1Line 1 Line 2

CB 2

D

2-winding power transformer with connected small delta tertiary load. Two lines (cables).

Application examples tapped lines

CB 1Line 1

Line 2

CB 2

Passive load

2-winding power transformer on tapped line. Two lines (cables).

Two terminal applications


Line 1CB 1 Line 3

CB 3

Line 2

CB 2

Line 4CB 3

Line 3

CB 2

Line 1

CB 1

Line 2

CB 2

Three terminal application.3-winding power transformer with small delta tertiary. Three lines (cables).

Four terminal application.2-winding power transformer, small delta tertiary. Four lines (cables).

D

D

Application examples multicircuit lines


Id >

Id > I

d > I

d >

Id >

Master-master configurationfor a five terminal line

Back- to- back communication


Id> Id>

Two terminal line with 1 ½ breaker

Two terminal line with 1 ½ breaker, redundant channels

Id>

Primary channels

Secondary channels

Id>



Id

>

Id

>

Id

>

Three terminal line with 1 ½ breaker



The Protected Circuit (Sydkratft’s 130 kV system)

CB 5

Sege, CurrentTerminal 1

Stjarneholm,

Current Terminal 5

CB 3

Fault:L1 - E

Rf = 50 Ω

CB 2 CB 4

Arrie, Current Terminal 2Svedala,

Current Terminal 4

3000/2 A

1500/2 A

CB 1

1000/2 A Trelleborg, Current Terminal 3

1200/2 A

12.9 km

4.8 km

15.5 km

22.0 km

2.9 km

1000/2 A

3.9 km

5-terminal application in Sweden


B

H

BR

0 t

The second harmonic component appearsas a characteristic quantity in a transformer inrush current. It is also possible to monitor

the shape of a current signal

Second harmonic stabilisation Wave form stabilisation

- wave block

0 20 40 60 80 100 120 140

2

4

6

8

iL1

iL2

iL3

Transformer inrush current

Transformer Inrush Current Stabilisation


Heavy internal fault

CT saturation will cause a second harmonic component in the secondary current

Second harmonic blocking normally causes delayed operation in

case of CT saturation



Second harmonicstabilisation (10-25 %)

- conditionally- always

Wave blockdI/dt ≈≈≈≈ 0 in 4 ms

Transformerswitch on

60 seconds 6 seconds

Heavy external fault- Ibias > 1,25 Ir- No trip request

Activated

How to avoid delayed trip for heavy internal faults?


Inactivate second harmonic blocking

Normal operation

Same as in RET 521


B

H

The fifth harmonic component appears as a characteristic quantity in the transformer

magnetizing current during overvoltage.

0 20 40 60 80 100 120 140 160

-3

-2

-1

1

2

3Magnetizing current at system overvoltage

iL1

iL2

iL3

Transforrmer Overvoltage Stabilization

The fifth harmonic componentis used for stabilization


• Protection independent direct transfer trip

• Security achieved with bit check

• Separate transfer trip via the channel for the differential protection

• 8 transfer trip channels

Trip R

Trip S

Trip T

Comm.

Difff.etc..

Transfer trip.

Ι

U

Transfer trip


Communication of binary signals

In each telegram there are eight binary signals freely

configurable by the user in CAP configuration.

These signals can be used for any purpose.


Line differential protection for 2 to 5 terminal lines

Back up distance protection

Instantaneous non-directional phase overcurrent protection

Time delayed 4 step directional/non-directional phaseovercurrent protection

Thermal overload protection

Breaker failure protection

Current circuit supervision

Instantaneous non-directional residual overcurrentprotection

Time delayed 4 step directional/non-directional residualovercurrent protection

Multifunction features


Current circuit supervision

Autorecloser 1- and/or 3-phase, single or double circuit breaker

Synchro-check and energizing-check, single or double circuit breaker

Disturbance recorder

Trip value recorder

Event recorder

Service value reading U, I, P, Q, S, f, cosj, I diff, I bias, I remote

Trip logic for single and three pole tripping of up to two breakers

Multifunction features


A differential current does not always mean a fault, but -

Idiff

Line Differential Protection


Documents

Gustavo Forster RED 670 Line Differential ABB …ceb5.cepel.br/arquivos/artigos_e_documentos/prot_dif/abb.pdfRED 670 Line Differential Protection Terminal Gustavo Forster [email protected]