THERMOMETERS FOR POWER TRANSFORMERS …maxsteel.sg/.../accessories_for_power_transformers.pdf · File : OTI-WTI ing UNCONTROLLED COPY Rev. 3 dtd 10/10/08 THERMOMETERS FOR POWER TRANSFORMERS

File : OTI-WTI ing UNCONTROLLED COPY Rev. 3 dtd 10/10/08

THERMOMETERS FOR POWER TRANSFORMERS Oil temperature indicators – O.T.I.

Winding temperature indicators (thermal image) - W.T.I. In power transformers it is necessary to have the control of the oil temperature and of the winding temperature, using high quality instruments, reliable and with good precision. Our MSRT family of O.T.I and W.T.I. is the result of a deep study and long research: they join an high quality standard with some innovative solutions which reduce in a big way the wiring time and the mounting cost on the transformer: - all the connections to the alarm , tripping, fan control circuits shall be done only on the termination box under the instrument dial (see page 5.25.3) - our W.T.I. have the heating resistance directly inside the sensor bulb pocket, wired up to the termination box - the heating resistance of our W.T.I. is calibrated for the rated current of the CT on the secondary of the power transformer, offering the advantage of reducing the wiring time ( no need of matching unit and direct connection between CT and WTI) with big savings on direct and indirect costs 1.0 Features: High performance instruments, fitted with two/three/four adjustable microswitches (SPDT = change over circuit), organic liquid filled (no mercury)- 6 mt armoured capillary tube, with built-in compensation- 1"BSP bulb 150 mm long (other connections or bulb length available upon request)- max pointer- back flange or elastic suspension (vibration dampener)- breathing device (to avoid dew on the transparent window)- aluminium housing (coated with an epoxy primer and finish paint)- cable box with an easy-connecting terminations block- polycarbonate window

1.1 Manufacturing program: -MSRT 100 & 150-LJB ,page 5.22 (drg 1272),-O.T.I.-: oil temperature indicator with two microswitches; side cable box -MSRT 150-Y, page 5.23 (drg 1242/A),-O.T.I.-: oil temperature indicator with two or three or four microswitches; bottom cable box -MSRT 150-W, page 5.24 (drg 1242/B),-W.T.I.-: winding temperature indicator with two or three or four microswitches

2.0 Characteristics (common for O.T.I. & W.T.I.): -Protection degree: IP65 -Range:-20..130° C/ 0..150 °/0..160° - (other ranges available upon request); black figures on a white dial -Precision class: 1,5 -Max pointer: resettable from the front window -Microswitches breaking capacity (no-inductive load): 5 A/250 V ac , 50 Hz, ( 250 mA/250 V dc) -Switching accuracy: 2 % scale value -Microswitch pointers: setting dial with 2/3/4 pointers, which are accessible through the front window; full range adjustment -Min set point interval between two switches : approx. 4 °C -Insulation test: 2000 V for 60" (50Hz) -150 mm bulb in copper alloy with 1" BSP connector (other connector size or bulb length upon request)-Copper capillary tubing, 6 mt long, with flexible galvanised steel PVC covered armouring (stainless steel or copper armouring and different length available upon request) 3.0 Characteristic (for W.T.I.-thermal image): -Heating resistance: bulb with built-in resistance (pag 5.25.3-Fig 1), wired directly to the terminations-block inside the cable-box -Rated current of the heating resistance: 1 A/1,5 A/ 2 A/ 5 A according to customer requirement, to be indicated when issuing the order, equal to the rated current of the CT -Terminations-block (pag 5.25.3-Fig 4): 3 terminations for each switch + 2 terminations for the CT connection (power supply to the heating resistance) + 2 terminations for the AMeter (adjustment of the heating current) + ground termination; -Adjusting Potentiometer for calibration of temperature rise: located inside the instrument; regulating knob accessible through the front window; inside each WTI there is a sheet with instructions for calibration and the heating curves. Accessories -back flange (page 5.25.1 drg 1242/C fig 2) -elastic suspension (page 5.25.1 drg 1242/C fig 1) -transmitter : one (or eventually two) PT100 probe, suitable for reading temperature in a control room through a panel receiver or for computerised temperature monitoring, can be fitted, upon request, inside the bulb pocket, as shown at page 5.25.3; the PT100 probe is pre-wired up to the terminations-block inside the cable box. The PT100 probe is a Platinum alloy resistance, manufactured in accordance with DIN43670 standards (temp. coeff. 0,00385), having the characteristic to change its own resistance with temperature as follows: 100 ohm at 0° C, 109,73 ohm at 25° C, 138,5 ohm at 100° C, 157,32 ohm at 150° C. -panel receiver for remote monitoring (see page 5.25.3): electronic digital receiver, DIN sizes 96x48 mm).

File : OTI-WTI ing UNCONTROLLED COPY Rev. 3 dtd 10/10/08

4.0 Order instructions When issuing an order or asking a quotation please specify: -type (MSRT-150-LJB or Y or W) -capillary length if different from the standard length (6 m) -bulb connection and length (if different from the standard DIN style 1" M x 150 mm) -range -nr of microswitches -back flange or elastic supsension mounting -CT rated current (for WTI only) -accessories and/or any other special requirement Adjustment of the winding temperature rise (MSRT 150 W) The temperature rise of the winding at the rated power of the transformer is a known data. To make the adjustment of the temperature rise, please operate as follows: -The bulb must be immersed in well filled with transformer oil -Open the cable box and locate the terminals T-T and A-A inside the cable box (page.5.25.3) -Insert the A-meter probes in the terminals A-A -Remove the jumper A-A -Inject a current. corresponding (CT ratio) to the rated power of the transformer in the terminals T-T -Adjust the current rotating the knob of the potentiometer on the dial until you read on the A-meter the value of the current corresponding to the desired temperature rise given by the specific curve for the rated current of the heating resistance (CT rated current) -Await few minutes until the transitory is finished, check the temperature is stabilised at the desired value and make the final adjustment if necessary. -Replace the jumper A-A -Remove the A-meter The W.T.I. is now ready Please note that when delivered, the potentiometer knob is positioned at the minimum resistance value. 5.0 Drawings description (pag5-22, pag5-23, pag5-24) : pos. 1 housing pos. 2 locking ring pos. 3 M14 connecting screw for elastic suspension (drg. TN 1231) pos. 4 breathing device pos. 5 capillary outlet pos. 6 oil/winding temperature dial pos. 7 microswitches setting dial pos. 8 max pointer pos. 9 miscroswitches setting pointers pos. 10 terminations block pos. 11 polycarbonate window pos. 12 WTI adjusting potentiometer for drg. TN 1242/B only

File : POWER PRD ing UNCONTROLLED COPY Rev. 4 dtd 27/10/08

PRESSURE RELIEF DEVICES FOR POWER TRANSFORMERS

(with electric contacts) GENERAL FEATURES When it is required to limit the pressure rise inside a tank, in order to prevent an excessive mechanical stress of the walls, it is necessary to use a safety valve set at a precise overpressure value. The tank of oil-immersed transformers is usually fit with this kind of protecting device; as matter of fact, in case of short-circuit due to an insulation failure, the dielectric arc between alive parts vaporises the surrounding insulating fluid which generates a quick rise of the pressure inside the tank, with the risk of permanent deformations, or, even, of the failure of the tank walls with the consequent flow-out of hot oil. Due to the rapidity of this event, it is necessary to mount on the transformer an adequate protecting device which relieves quite suddenly the excess of pressure generated inside the tank by the above mentioned failure. Our Pressure Relief Devices “ VP “ have this protective function. WAY OF WORKING The way of working of above device is very simple: each time the pressure inside the transformer tank reach the operating pressure of the PRD, the shutter lift slowly from its rest position disjoining from the main tightening gasket (pos 9 of the attached sketch); in this condition the excess of pressure can’t be released in the environment, being the shutter still in contact with the external gasket (pos 10 of the attached sketch). Now the internal overpressure operates on the whole internal surface of the shutter, which is bigger than the initial surface: consequently, the strength acting on the shutter is much higher than the spring-load on the other side; this brings to a quick and high lifting of the shutter followed by an equally fast reclosure as the excess of pressure is released in a very short time through the big opening created by the shutter lifting. GENERAL FEATURES of our “ VP “ devices - Body, connecting box and shutter in cast aluminium, paint protected. - Screws, nuts, fasteners, pins in stainless steel or nickelplated brass. - NBR rubber gaskets (other kind of gasket material available upon request for use at extremely low temperatures). - Oil spray protection (upon request) in stainless steel. - Springs in high quality steel, finish shotblast plus epoxy paint (corrosion protection). - Electric contacts (upon request), one or two, changeover, inside the connecting box with IP67 protection degree. - All the components of our PRD are positioned outside the fixing flange, with two big advantages:

a) Impossible to loose inside the tank any components like small nuts or pins. b) Without anything protruding inside the tank it is possible to locate the PRD in those points where there are more risk of generation of the overpressure, reducing the possibility of deformation of the tank.

- Optic signal: a big red semaphore protrude outside the cap and indicates the PRD has operated; the semaphore need to be manually reset; the semaphore is a standard accessory on all our “VP” valves, either with or without oil spray protection or contacts.

MANUFACTURING PROGRAM Three sizes: - VP 50, pag5-31, up to 3000 dm3 of oil inside the tank. - VP 80, pag5-33, up to 9000 dm3 of oil inside the tank. - VP 150, pag5-35, up to 25000 dm3 of oil inside the tank, or more. For bigger volumes of oil it is common practice to use more valves. ACCESSORIES Our Pressure relief devices “VP” can be fit with the following accessories, all independently each other: - Oil spray protection: useful to give an orientation to the oil flow towards draining systems in order to avoid damages or

injuries to persons due to hot oil. - One or two independent electric contacts ( microswitches, changeover-wiring diagram, inside the connecting box);

contacts are operated through a lever by the shutter and need to be manually reset in case of operation.


ELECTRIC CONTACTS Protection degree: IP67 Contacts in Silver/Nickel plated Breaking capacity at 250 V (ac 50/60 Hz): 5A Breaking capacity at 125 V (dc): 1 A Current (min/max): 0,1 / 10 A DYNAMIC CHARACTERISTICS (MECHANICAL STRESS WITHSTAND) - Sinusoidal vibrations with frequency < 120 Hz and amplitude < 250 µm - Dynamic stress with the following accelerations:

Max 3g in any direction, sinusoidal, amplitude < 20 mm. Shock, max 10 g, in any direction.

CHOICE OF THE VALVE AND MOUNTING INSTRUCTIONS The choice of the size of the valve depend form the space available and from the quantity of oil inside the tank. Looking at the safety and at the operating rapidity it may be preferable to use more than one valve, eventually of smaller size. Each valve can be mounted either vertically either horizontally on the transformer tank, the nearest possible to the point where a failure may occur, or on barycentric position if there are more than one critical point, usually nest to the transformer columns. CLIMATIC CONDITIONS Generally the limitation to the use of this kind of valve stays in the gasket material. Here below we give you few data regarding three type of different gasket material, suitable for use in different ambient conditions, in mineral oil or silicon fluid, with humidity: 95% at 20°C; 80% at 40°C; 50% at 50°C. a) Standard execution (N)

Gasket material: NBR rubber. Ambient temperature (min/max): -20°C/50°C Oil Temperature (min/max): -20°C/110°C

b) Low temperature execution (F) Gasket material: special kind of NBR rubber suitable for low temperature. Ambient temperature (min/max): -40°C/50°C. Oil Temperature (min/max): -40°C/110°C

c) High temperature execution (V) Gasket material: Fluor-rubber. Ambient temperature (min/max): -15°C/50°C Oil Temperature (min/max): -14°C/150°C

CORROSION PROTECTION All the part of the valve made in aluminium, corrosion protected with a coating (a oil resistant primer coat, approx 50 µm thick, on all the surfaces, plus a polyuretahanic coat, RAL7030 colour, only on the surfaces exposed to the external atmosphere, with a total coating thickness of approx 100 µm. Oil spray protection and screws: in stainless steel. Please contact our design department every time the specifications require a special valve, giving us full details.


OPERATING PRESSURE VALUES Our Pressure Relief Devices “ VP “ can be calibrated at an operating pressure value between 30 kPa and 150 kPa. The value indicated on the identification label is the nominal value ( Pn ) of the operating pressure. It is necessary to define other value of the operating pressure:

- Pe: working pressure, max value of the internal pressure at which there are no leaks of gas or of oil - Pt : tightening pressure, which is the max value of the internal pressure at which the valve is reclosing during testing - Pmin & Pmax: Min & Max operating pressure, which are the Min and Max value of the internal pressure at which the valve is operating (the difference between the two values is equal to the tolerance of the nominal value)

Pn Pe P min P max Pt30 25 30 37,5 27 40 33 38 46 35 50 42,5 47,5 57,5 44,5 60 52 57 66 54 70 61,5 66,5 77 63,5 80 71 78 86,4 73 90 80,5 85,5 97,2 82,5 110 105 110 118,8 107 130 125 130 136,5 127 150 145 150 157,5 147

Vacuum withstand test: 10 torr Pressure withstand test: 4 bar ORDER INSTRUCTIONS When issuing an order or asking a quotation, please specify the following: - Size of valve. - If oil spray protection is required. - Operating conditions (material of gasket: standard NBR, low temperature, high temperature). - Wiring diagram. - Nominal value of the operating pressure, Pn. See table in next page. Example Nr 3 PRD type VP080P0NH050; means that are required nr 3 valve VP080 with protection, climatic standard operating conditions, wiring diagram H (1 changeover contact) and setted at 50 Kpa. SPECIAL EXECUTIONS It is possible to supply special valves, which are in accordance with special requirements.


VP080 P0 N H 0 5 0

PR

OD

UC

T

A

ND

SIZ

E

PR

OT

EC

TIO

N

OP

ER

AT

ING

C

ON

DIT

ION

S

WIR

ING

D

IAG

RA

M

OP

ER

AT

ING

P

RE

SS

UR

E

VA

LUE

kP

a

LEGENDA

025 OPERATING VALUE 25kPa 030 OPERATING VALUE 30kPa 035 OPERATING VALUE 35kPa 040 OPERATING VALUE 40kPa 045 OPERATING VALUE 45kPa 050 OPERATING VALUE 50kPa 055 OPERATING VALUE 55kPa 060 OPERATING VALUE 60kPa 070 OPERATING VALUE 70kPa 080 OPERATING VALUE 80kPa 085 OPERATING VALUE 85kPa 090 OPERATING VALUE 90kPa 110 OPERATING VALUE 110kPa 130 OPERATING VALUE 130kPa 150 OPERATING VALUE 150kPa F W/OUT CONTACTS H 1 SPDT CONTACTS W 2 SPDT CONTACTS N STANDARD CONDITIONS NBR GASKETS L LOW TEMPERATURE GASKETS V HIGH TEMPERATURE VITON GASKETS F0 WITHOUT PROTECTION P0 WITH PROTECTION

QT

WITH OIL DUCT (ALWAYS AND ONLY FOR VP150-QT)

VP050 PRD VP50 VP080 PRD VP80 VP150 PRD VP150 &VP150-QT

File : VP150QT UNCONTROLLED COPY Rev. 5 dtd 27/10/2009

PRESSURE RELIEF DEVICE VP 150 QT


1.0 Features

The pressure relief valve VP150QT have been specially designed for use on transformers in which is not admitted any external pollution due to oil released during its operation (i.e. transformers installed on trains or ships). The pressure relief valve VP150QT open when the pressure inside the tank increases over the set operating value, following for example a failure or a short circuit. By releasing oil it reduces the pressure in the tank and by means of the electric contact, and the optical indication the pressure relief valve indicates that a fault has taken place. The oil-tight cover contains the oil released by the valve when opening and provides a flanged connection on which a pipe can be attached that ducts the oil in the desired direction.

2.0 Construction features o Materials and components

Flange, shutter and cover are made of cast aluminium; Fittings are made of stainless steel or nickel coated brass; Gasket materials are as specified for the different executions (ref to paragraph 6); Springs are made of spring steel, sandblasted and painted with epoxy powders; External screws are made of stainless steel.

o Reference drawings Assembly , overall dimensions and wiring diagram: drawing 1373 Cross section: drawing 1372

o Construction The pressure relief valve type VP150QT is a spring operated safety valve, consisting of a mounting flange with the central opening closed by a spring loaded shutter; the springs are compressed between shutter and pressure ring, which is assembled to the flange by columns. No part of the pressure relief valve reaches inside the transformer tank. A specially designed gasket assures the oil-tightness between flange and shutter when the valve is closed. The oil-tight cover encases the valve completely and provides the flanged connection on which a pipe can be attached.

o Springs The springs are of the compression type, designed so as to have a limited force gain with the stroke.

o Operation indication The pressure relief valve VP150QT has an optical indication that the valve has operated; this optical indication consists of a red pin showing about 30-40 mm over the top of the valve cover when the valve has operated because of an internal overpressure. The pin is spring loaded so that even in case of partial openings of the valve due to small or short-duration overpressures the pin is nevertheless expelled completely. The operation of the pressure relief valve is also indicated by one or two electric contact, which have the characteristics indicated paragraph 5.

o Oil-tightness and resistance to pressure The pressure relief valve VP150QT:are oil tight to oil at 100°C up to tightness test pressure Pt, which depends on the setting pressure; are mechanically and electrically resistant to vacuum (10 torr);have a mechanical resistance to pressures up to 4 bars.

o Resistance to dynamical stress The pressure relief valve VP150QT can operate without undue operation in following conditions: Sinus vibrations with frequency <= 120 Hz and amplitude <= 250 µ; Dynamical conditions causing following accelerations: - Max 3g in all directions, sinus vibration, amplitude <= 20 mm; - Shock condition with max 10 g in all directions.

o Surface protection Flange, shutter, cover and contact’s casing are painted internally and externally with one primer coat of epoxy paint and externally with a finishing coat of polyurethane paint colour RAL 7030. The primer coat on the internal surfaces in contact is compatible with transformer mineral oil up to temperatures of 120°C. Total thickness of two coats is 120 microns; special painting cycle can be provided for transformer located in very polluted areas


3.0 Operation and installation

o Operation Should an overpressure inside the transformer tank build up due to short circuit or else, higher than the set operation pressure of the pressure relief valve, the shutter lifts from the flange propelled by the pressure, thus opening the discharge opening. The oil can flow out thus reducing the overpressure; at the same time the optical indication and the electric contact show that the valve has operated. When the overpressure has been discharged the valve shuts again automatically to complete oil-tightness. The oil discharged by the valve remains inside the oil-tight cover and can be ducted to an appropriate container by a pipe flanged to the cover. Thanks to the design of the pressure relief valveVP150QT and their springs, the full opening is reached even for small overpressures in a matter of milliseconds, so as to reduce the resistance to the oil flow.

o Importance of the electric contact Real life tests have shown, that failures of the transformer followed by sudden pressure increases, such as for instance short circuits, induce the operation of the pressure relief valve in time spans which are considerably shorter than that of other safety devices, such as the Buchholz Relay.

o Installation Use one pressure relief device for each 35.000 litres of transformer oil capacity of fraction thereof The pressure relief valve should be installed, either in horizontal or vertical position, on the transformer tank, as near as possible to possible failure sources or in a central position to such sources.

4.0 Setting The setting of the pressure relief valve VP150QT is effected by choosing a different spring for every operating pressure value; therefore the setting of the pressure relief valve can be changed only at the factory, thus eliminating possible misuses. The performance of the pressure relief valves depends from the test fluid and the layout of the transformer tank. The pressure values listed below are obtained by operating the valves with compressed air on a test bed having a compressed air volume of 150 dm3. To avoid oil leakage or undue operation of the valve, the operating pressure must be chosen so that in normal operation the corresponding maximum operating pressure is never reached. In following table are indicated the tolerance of the pressure setting, the service pressure, the closing pressure and the tightness pressure for the different nominal pressure settings.

Pn Pmin Pmax Pe Pc Pt [bar] - % [bar] + % [bar] [bar] [bar] [bar] 0,3 0 0,30 30 0,39 0,19 0,18 0,24 0,4 5 0,38 20 0,48 0,31 0,26 0,32 0,5 5 0,48 15 0,58 0,35 0,30 0,43 0,6 5 0,57 10 0,66 0,46 0,35 0,54 0,7 3 0,68 10 0,77 0,53 0,44 0,63 0,8 3 0,78 8 0,87 0,62 0,50 0,72 0,9 3 0,88 8 0,98 0,74 0,60 0,81 1,1 0 1,10 8 1,19 0,88 0,75 0,99 1,3 0 1,30 8 1,40 1,00 0,95 1,17 1,5 0 1,50 7 1,60 1,20 1,10 1,35

Pn (nominal pressure) is the setting pressure of the pressure relief valve, on which the tolerance must be applied in order to determinate the minimum and maximum operating pressure. Pmin, Pmax (minimum and maximum operating pressure) are the limits of the pressure range inside which the pressure relief valve must operate. Pe (service pressure) is the maximum pressure the pressure relief valve can withstand without showing oil leakage or oil loss. Pc (closing pressure) is the minimum pressure at which the valve closes after operation Pt (tightness test pressure) is the pressure at which the valve if tested during the leakage tests.


5.0 Electric contacts

The contacts are microswitches changeover type and are mechanically operated by the shutter; after operation contacts remain in trip position and have to be resetted manually by pushing the red pin indicator located on the cover of the PRD; contacts are assembled inside the cover and are connected to the termination of terminal box by a cable

o Characteristic of contact (low current contacts are available on demand) Degree of protection of contact IP 67 Lever and pushbutton Stainless steel Contact material Nickel coated silver Mechanical endurance of contact 1x107 cyles Temperature range -40°C - +125°C Standard interruption power AC 250V-5A - DC 125V-1A Short endurance interruption power DC 125V-1,5A Insulation to earth at 20°C 2.500V Insulation of open contact at 20°C 1.500V Minimum and maximum current 1,0 - 10A Degree of protection of terminal box IP 65 Insulation to earth at 20°C 2.500V

6.0 Compatibility of installation The installation compatibility of the pressure relief valve VP150QT depend mainly on the material used for the gaskets; therefore the executions differ because of the used gaskets.

o Standard execution – nitrile rubber gaskets (N) Admitted operating conditions are: Environmental conditions. Ambient temperature: -20°C to +50°C Relative humidity: 95% to 20°C - 80% to 40°C - 50% to 50°C Insulating liquid (transformer mineral or silicon oil). Temperature: -20°C to + 110°C

o Execution L - nitrile rubber gaskets for low temperatures (L) Admitted operating conditions are: Environmental conditions. Ambient temperature: -40°C to +50°C Relative humidity: 95% to 20°C - 80% to 40°C - 50% to 50°C Insulating liquid (transformer mineral or silicon oil). Temperature: -40°C to + 120°C

o Execution V – fluor rubber gaskets (Viton V) Admitted operating conditions are: Environmental conditions. Ambient temperature: -15°C to +50°C Relative humidity: 95% to 20°C - 80% to 40°C - 50% to 50°C Insulating liquid (transformer mineral or silicon oil). Temperature: -15°C to + 150°C

o Special executions For other environmental and/or operating conditions to be examined individually.

7.0 Ordering Instructions When ordering must be defined following data: - Model of pressure relief device : VP150 QT

- Type of gasket required (ref to paragraph 6) : N; L; V - Wiring diagram (ref to drawing 1373) : H; W - Nominal operating pressure in bar See table in next page

Example Nr 3 PRD type VP150QTNH050; means that are required nr 3 valve VP150QT, climatic standard operating

conditions, wiring diagram H (1 changeover contact) and setted at 50 Kpa.


VP150 P0 N H 0 5 0

PRO

DU

CT

AND

SIZ

E

PRO

TEC

TIO

N

OPE

RAT

ING

C

ON

DIT

ION

S

WIR

ING

DIA

GR

AM

OPE

RAT

ING

PR

ES

SUR

E

VALU

E kP

a

LEGENDA

025 OPERATING VALUE 25kPa 030 OPERATING VALUE 30kPa 035 OPERATING VALUE 35kPa 040 OPERATING VALUE 40kPa 045 OPERATING VALUE 45kPa 050 OPERATING VALUE 50kPa 055 OPERATING VALUE 55kPa 060 OPERATING VALUE 60kPa 070 OPERATING VALUE 70kPa 080 OPERATING VALUE 80kPa 085 OPERATING VALUE 85kPa 090 OPERATING VALUE 90kPa 110 OPERATING VALUE 110kPa 130 OPERATING VALUE 130kPa 150 OPERATING VALUE 150kPa F W/OUT CONTACTS H 1 SPDT CONTACTS W 2 SPDT CONTACTS N STANDARD CONDITIONS NBR GASKETS L LOW TEMPERATURE GASKETS V HIGH TEMPERATURE VITON GASKETS F0 WITHOUT PROTECTION P0 WITH PROTECTION QT WITH OIL DUCT (ALWAYS AND ONLY FOR VP150-QT)

VP050 PRD VP50 VP080 PRD VP80 VP150 PRD VP150 &VP150-QT

File : CPR UNCONTROLLED COPY Rev. 4 dtd 15/07/09

PROTECTIVE RELAY TYPE CPR FOR RUBBER BAG CONSERVATOR


1 General Features

1.1 Characteristics Power transformer usually prevent contact of mineral oil with air (that contains water due to humidity) us-ing a rubber bag fitted inside conservator tank. If there is an intrusion of air inside the conservator (due i.e. to a microscopic accident inside rubber bag) this must detected. The gas detector relay type CPR has been specially developed in order to detect this kind of failure. The relay is designed in a way that it is able to collect the gas inside himself and give an electric signal as soon as the gas accumulated reaches a predetermined value. .

1.2 Field of Use

The gas detector relay type CPR may be used with the following characteristic values: Fluid mineral oil pressure in the conservator max 1,2 bar working temperature from - 20°C to + 100°C resistance to vibrations up to 3 g on all axes resistance to shock up to 10 g on all axes

2 Construction Features, Finish and Accessories

2.1 Construction Features

With reference to drawing and its nomenclature, which also indicates the materials, the device is con-structed as follows: • a body made in aluminium alloy equipped with a connecting flange pos. 8 that permit mounting on

conservator by using a flat gasket and 4 screws M10 • a cover pos. 9 equipped with a push bottom pos. 3 and a gas release cock pos. 2 that allow check-

ing the contact and draining air from the body. • a terminal box pos. 4, including the trip terminals pos. 6, the earth screw pos. 10 and a cable gland

PG16 for connecting to the external circuits

2.2 Finish

In standard execution, all cast parts are protected by one coat of epoxy primer and one coat of polyure-thane paint (total thickness 80 µm), final colour RAL 7030 and screws and washer are in stainless steel; the protection degree of the device is IP 55. Therefore the device is suitable for outdoor installation in tropical climate and with industrial pollution.

2.3 Accessories

The device is supplied with its assembly NBR flange gasket.

3 Wiring Diagrams and Contact Performance

3.1 Wiring diagrams

The relay is equipped with one magnetic contact, reed type, that operate when gas inside relay reaches the preset value. Available wiring diagrams are : • Wiring diagram ME : 1 normally open contact • Wiring diagram MT : 1 change-over open contact

3.2 Contact's Performance 3.2.1 Normally open contacts(N/O)

Shock resistance: 50 g for 11 millisecond without false operation Vibration resistance: min 6 g with a frequency range between 3 and 35 Hz without false operation Insulation resistance: 1000 mega ohms at 20°Cminimum Operate time: 3 milliseconds Release time: 5 milliseconds Life expectancy: 10 millions operations


Max D.C. resistive load (W): 250 Max A.C. resistive load (VA): 400 at 50 Hz Max D.C. inductive load (W): 250 (the contact can break 1A at 250 V.D.C. with L/R=40 millisecond.) Max A.C. inductive load (VA): 400 at 50 Hz Constant current (A): 3 Max switching voltage (Vrms): 250 Min switching voltage (V): 24 Dielectric strength (Vrms): 800 Max contact resistance (MΩ): 500

3.2.2 Change-over contacts (SPDT) Max D.C. resistive load (W): 130 Max A.C. resistive load (VA): 200 at 50 Hz Max D.C. inductive load (W): 130 (the contact can break 1A at 110 V.D.C. with L/R=40 millisecond.) Max A.C. inductive load (VA): 250 at 50 Hz Constant current (A): 1 Max switching voltage (Vrms): 250 Min switching voltage (V): 24 Dielectric strength (Vrms): 800

4 Operation The protective relay CPR operate as follows: • When the atmospheric air is intruded inside the transformer due to rubber bag failure (break or gas-

ket failure) or to microscopic accident it will be collected inside the relay and will cause rotation of float inside the relay (rotation of float and quantity of gas can be detected from inspection window); a permanent magnet rigidly connected to the float operates the reed contact.

5 Mounting, Adjustment and Maintenance

5.1 Mounting The protective relay CPR has to be mounted on the top of conservator (see mounting sketch) using 4 screws and nuts M10. Tightening is obtained using a flat gasket made in NBR. After mounting and before setting to work, air inside body have to be removed by opening gas release cock pos. 2. Circuit can now be tested by pressing push bottom pos. 3.

5.2 Maintenance

The protective relay CPR do not need periodic maintenance; however it is advisable to check regularly the electric contact and the freely movement of float; this test can be made easily y by pressing the push button 3.

6 Order Specifications When ordering it is necessary to indicate • Size:

CPR 1 : operating volume 450 cm³ CPR 2 : operating volume 200 cm³

• Wiring diagram (ME or MT) • Special requirements Example : To order n r 1 protective relay CPR with 1 magnetic contact N/O gas operating value 450 cm³ (type 1) please indicate the following:

Nr 1 relay CPR-ME1


7 Part denomination of protective relay CPR

Pos. Part denomination Material

0 Body Aluminium alloy

1 Inspection window Trogamid

2 Gas release cock Brass

3 Push button for checking electric circuits Brass

4 Terminal box Aluminium alloy

5 Cable gland PG16 Nylon

6 Trip terminals Brass

7 Plug PG16 Nylon

8 Mounting flange Aluminium alloy

9 Cover Aluminium alloy

10 Earth screw Brass

File : SCFR2 UNCONTROLLED COPY Rev. 3 dtd 10/10/08

OIL FLOW INDICATOR SCFR 2

1 General Features

1.1 Characteristics

The circulation indicators Series SCFR2‚ are designed to check the circulation of dielectric fluids, nor-mally mineral oils, in the cooling installations of electric transformers. The possibility of using them with other fluids and/or in other types of installation depends on the fluid in circulation and its compatibility with the materials used in the construction of the device and must therefore be looked into in every case.

The dimensions, the assembly and all other characteristics are according to French standard NF C 52-122. The circulation is indicated optically by an arrow that indicates on a dial the running (M) or the stop-page (A) of the circulation pump and electrically by one or two electric contacts. The indicators Series SCFR2‚ only show that the flow speed inside the pipeline has the required value. The optical indication may not be proportional to the velocity.

The operation of the indicator Series SCFR2‚ is based on the dynamic thrust of the flowing oil on a detec-tion paddle placed inside the pipe; the dimensions of the paddle depend on the diameter of the pipe. An adjustment device allows the triggering point to be altered within certain limits, even after the indicator has been mounted, in order to adapt it to the real flow conditions.

1.2 Field of Use

The circulation indicators Series SCFR2‚ may be used with the following characteristic values:

1.3 Special Features

On the basis of the experience of the previous series, special features have been included in the design of the circulation indicators Series SCFR2, aimed at simplifying the choice of the device, making inter-changeability easy and allowing the user to modify the working characteristics, should he so desire.

• The diameter of the dial and the choice of colours for the dial and the arrow make the reading easy even from distance;

• the construction in two separable parts, mounting flange with detection paddle and adjustment sys-tem, and indicator with optical and electric indication, allows the indicator to be removed from the in-stallation for repair or during shipment of the transformer while having with the pipeline still closed by the flange. Therefore it is possible to modify or replace the indicator part of the device without having to empty the plant;

• the transmission of the paddle movement is by magnetic transmission so as to guaranteeing a per-fect seal;

• the adjustment system is simple and reliable; the adjustment can be made even after the device has been mounted on the pipeline in order to adjust the indicator to the real operating conditions.



With reference to drawing SCFR2-CROSS SECTION and its nomenclature, which also indicates the ma-terials, the device is constructed as follows:

• flange 2.0 allows the device to be assembled on the pipe; the gasket in groove 2.1 assures the seal;

pipeline diameter from 80 to 400 mm flow speed from 0,5 to 3,0 m/sec fluid mineral oil pressure in the pipeline from 0,0 to 5,0 bar working temperature from -20°C to +120°C resistance to vibrations up to 3 g on all axes resistance to shock up to 10 g on all axes


• the adjustment assembly 2.2, fixed to flange 2.0 by four screws 2.3, includes one end of the mag-netic transmission, the return spring 2.5 and the detection paddle 2.6;

• the indicating instrument 1.0 with the optical and electrical indication is mounted on flange 2.0 by the screws 1.5 and the lateral screw 1.6;

• a terminal box 3.0, attached to the instrument 1.0 and closed by a cover 3.1, includes the terminal board 3.2 which is used to connect the switch 3.3 to the external circuit as well as an earthing screw.

2.2 Finish

In standard execution, all cast parts are protected by one coat of two-pack epoxy primer and one coat of two-pack polyurethane paint, final colour RAL 7031 and screws and washer are in stainless steel; the protection degree of the device is IP 55 and of the contacts IP 67. Therefore the device is suitable for fit-ting in the open even in tropical climate and with high industrial pollution. Special versions are available for particularly severe climatic and/or aggressive atmospheric conditions.

2.3 Accessories

The device is supplied with its assembly gasket. A cable gland is supplied on request.


3.1 Wiring diagrams In the following table are shown all the standard wiring diagrams (special wiring diagrams are provided on demand)

WD N°

Term. Pos. in NE

Functional description of wiring diagram Operates at

00 Without contacts, only optical indication

1-2 Open F0

1-3 Closed 1 changeover contact for minimum flow minimum

1-2 Open G0

1-3 Closed 1 changeover contact for maximum flow maximum

AA 1-2/4-5 Open

BB 1-3/4-6 Closed 2 contacts for minimum flow minimum

DD 1-2/4-5 Open

EE 1-3/4-6 Closed 2 contacts for maximum flow maximum

1-2 Open

1-3 Closed 1 changeover contact for minimum flow minimum

4-5 Open FG

4-6 Closed 1 changeover contact for maximum flow maximum

WD = Wiring diagram code N° Term. = Numbers that identify the terminals Pos. in NE = State of the contact in normal exercise. Corresponds to maximum flow.


3.2 Contact's Performance 3.2.1 Standard Contact (ST)

Changeover micro switch contact worked mechanically Degree of protection IP 67 Casing Poliester Gasket Fluorosilicon rubber Lever and push button Stainless steel Contact's material Silver, nickel coated Mechanical endurance of contact 1x10

7 cycles

Temperature range -40°C to +125°C Standard power of interruption (1x10

5 cycles) AC 250V/5A - DC 125V/1A

Maximum power of interruption (1.000 cycles) DC 125V/1,5A

Isolation to mass at 20°C 2.500 V Isolation of open contact at 20°C 1.500 V Minimum and maximum current 0,1 - 10A

3.2.2 Low Current Contact (BC) Same performance as standard contact except: Contact's material Gold Operation range 1 to 100 mA - 4 to 30 V

3.2.3 Electric circuitry Degree of protection of instrument casing IP 55 Insulation to mass 2.500 V Material of terminal board Tin coated brass

4 Operation

The circulation indicators Series SCFR2 operate as follows:

• the oil flowing in the pipeline hits the detection paddle 2.6, thus causing the shaft on which it is mounted to rotate by about 90°, against the force of the return spring 2.5;

• the dimension of the paddle is chosen according to the diameter of the pipe and the oil flow that it should detect;

• the tension in the return spring 2.6¸ is pre-set at the factory in the centre of the adjustment range; the set point may however be further adjusted by turning the adjustment assembly 2.2 after removing the fixing screws 2.3; this adjustment can be made with the flange 2.0 mounted on the pipe;

• the magnetic transmission transmits the rotation of the paddle to the arrow and operates at the same time the switches.


5.1 Mounting

The circulation indicators Series SCFR2 operate within the operating conditions indicated in chapter 1.2. The device is mounted on a flanged stub pipe, welded directly to the pipeline; the dimensions of the stub pipe should be as indicated in drawing SCFR2 – GENERAL OVERWIEW.

To mount the device on the pipeline, separate the indicator 1.0 from the flange 2.0 by removing the lat-eral screw 1.6 and rotating the instrument by about 10° anticlockwise so as to free the screws 1.5 from their holes; then attach the flange 2.0 to the pipe by screws M8, with the assembly gasket in groove 2.1.

After having attached the flange to the pipe, assemble the instrument 1.0 on to the flange again and check that the optical display is operating correctly by starting up and stopping the circulation pump.

If it is functioning correctly, carry out the electrical connection according to the desired wiring diagram.

If the optical or electrical indications are not correct, carry out the adjustment described later.

In order to make sure the signal paddle 2.6 is hit by the most uniform possible flow, avoid mounting the device immediately downstream of bends, necks or other parts which could cause turbulence in the flow; if this is impossible, the adjustment of the tension in the return spring 2.5, allows the indicator to be adapted to the real flow conditions.


5.2 Adjustment

The device is always supplied with the adjustment assembly set to position 3, so that it is possible to both increase and decrease the load of the return spring 2.5 in order to set the device for a higher or lower flow rate.

If the factory setting is not satisfactory adjust the setting as follows:

• remove the indicator 1.0 from flange 2.0 as described above, in order to get to the adjustment as-sembly 2.2 fixed on the flange 2.0 by the four screws 2.3;

• remove the four screws 2.3; even if there is pressure in the pipe the adjustment assembly cannot come off the flange 2.0; furthermore a gasket continues to guarantee the seal;

• turn the adjustment block until the notch 2.4 corresponds with one of the numbers on the flange, an-ticlockwise to increase the force of the spring 2.5 and trigger the device at a higher flow rate, and clockwise to have the opposite effect;

• replace the 4 screws 2.3 and the indicator 1.0 on the flange 2.0 and check that the adjustment made has the desired effect otherwise make a further adjustment.

5.3 Maintenance

The circulation indicators Series SCFR2 do not need periodic maintenance; however it is advisable to check regularly that they are operating correctly by starting up and stopping the circulation pump and checking that the optical and electrical display takes place as normal.

6 Order Specifications

When ordering it is necessary to indicate the type of device according to the table in drawing SCFR2 – GENERAL OVERWIEW, the diameter of the pipeline, the mounting position, type of contact (standard or low current) and the required wiring diagram. Standard cable entry thread is ¾”; should another thread be preferred and a cable gland be needed, this has to be mentioned in order.


Part denomination of drawing SCFR2-CROSS SECTION

Pos. Part denomination N° Material

1.0 Indicating instrument 1 Aluminium

1.1 Front glass holding rim 1 Aluminium

1.2 Front glass 1 Tempered glass

1.3 Dial 1 Aluminium

1.4 Arrow 1 Aluminium

1.5 Assembly screws of indicating instrument 1.0 on flange 2.0 4 Stainless steel

1.6 Lateral fixing screw 1 Stainless steel

2.0 Mounting flange 1 Aluminium

2.1 Gasket groove

2.2 Adjustment assembly 1 Brass

2.3 Fixing screws of adjustment assembly 2.2 4 Stainless steel

2.4 Adjustment mark

2.5 Return spring 1 Spring steel

2.6 Detection paddle 1 Brass

3.0 Electrical junction box 1 Aluminium

3.1 Junction box cover 1 Aluminium

3.2 Terminal board

3.3 Switch 1/2

File : CCL2 UNCONTROLLED COPY Rev. 3 dtd 10/10/08

OIL AND WATER FLOW INDICATOR CCL2

1 General Features

1.1 Characteristics

The liquid circulation indicators Series CCL2 are designed to detect the operation of circulation pumps in cooling installations, in particular those of electric transformers, and are therefore particularly suited for detecting the flow of oil or water in piping, respectively by types CCL2-O, for oil, and CCL2-A, for water. The possibility of using them with other fluids and/or in other installations depends on the fluid and its compatibility with the materials used in the construction of the device and must therefore be looked into in every case.

The presence of circulation is displayed optically by white and red indicators visible through two sight glasses and electrically by one or two electrical switches. The devices Series CCL2 only show that the liquid velocity inside the piping has the required value; therefore the optical display may not be pro-portional to the velocity.

The way the devices Series CCL2 work is based on the dynamic pressure applied by the moving fluid on detection disc paddle placed inside the pipe, whose dimensions depend on the diameter of the pipe itself and the flow rate that it will have to detect. An adjustment screw allows the triggering point to be altered, within certain limits, in order to adapt it to the effective local flow conditions.

1.2 Field of Use

The circulation indicators Series CCL2 may be used with the following characteristic values:

2 Special Features

Based on the experience of previous series, the design includes the following features, aimed at simplify-ing the choice of the device and its interchangeability, and allowing the user to modify the setting to a certain degree to allow for local flow conditions:

• two sight glasses placed perpendicularly to the direction of flow allow the optical display to be seen from both sides of the pipe and two cable entries, allow the electrical connection to be made from whichever side is most convenient; therefore the same device may be fitted indifferently with the flow from the left or from the right, provided the arrow engraved laterally on the flange points in the direc-tion of the flow;

• the tension in the return spring is adjustable after removing the top cover, even with the device mounted in the pipe; this allows the indicator to be adjusted to the real working conditions.

• the devices made for mounting in vertical piping are provided with a counterweight fitted to the lever activating the optical and electrical displays in order to counterbalance the weight of the paddle; all of the devices may be fitted with this counterweight, which may be added as needed.

It is necessary to point out that the devices are supplied ready to be mounted according to the informa-tion given in the order and that any possible modification afterward must be understood as exceptional. Furthermore it is also necessary to inform us of these modifications, quoting the serial number of the arti-cle, so that we can update our records as regard any future supply of spare-parts.

pipeline diameter from 50 to 400 mm flow velocity from 0,3 to 5,0 m/sec pressure in the pipe from 0,0 to 2,0 bar working temperature from -20°C to +120°C resistance to vibrations up to 3 g on all axes resistance to shock up to 10 g on all axes




With reference to drawings at end of this brochure and part description par 8 (which also indicates the materials), the device is constructed as follows:

• on one side of the body 1.0 there is the flange 1.0.1 for assembly to the pipe with the gasket seat; on the other side body 1.0 is connected to casing 2.0; in order to avoid errors during assembly two ar-rows engraved on the body 1.0 indicate the direction of flow;

• on the side facing the pipe, the flow detector paddle 3.1, which can rotate by about 22° around the shaft 3.1.1, is fitted to the body 1.0; through the pin 3.2.1 the paddle 3.1 causes the signal transmis-sion shaft 3.2 to rotate; the rotation of shaft 3.2 and therefore of the paddle 3.1 is limited by the stops 3.2.2; the protection 1.1 protects these parts from damage during transportation and mounting;

• shaft 3.2 passes through the body 1.0 and activates the optical and electrical display by means of lever 3.3, fitted to the shaft itself; the sealing along the shaft 3.2 is assured by gaskets;

• the optical display consists of two red and white dials 3.3.1 fitted to lever 3.3 and visible through the sight glasses 2.2; the electric signal takes place through 1 or 2 microswitches 3.0 fixed to the body 1.0 and triggered by the lever 3.3;

• the electrical connection with the microswitches and the earth screw 3.8 can be made through the terminal 3.7 and the cable entries 2.0.1 by removing the casing cover 2.1; on the inside of cover 2.1 plate 2.4 shows the wiring diagram and the serial number; cable 2.5 ties the cover 2.1 to the casing 2.0, preventing it from getting lost or swapped;

• spring 3.5 returns the lever 3.3 and therefore also the paddle 3.1 to their rest position; through de-vice 3.6 it is possible to adjust the tension of the spring 3.5 to adapt the detection to the local flow conditions.

3.2 Finish

In standard execution, all cast parts are protected by one coat of two-pack epoxy primer and one coat of two-pack polyurethane paint, final colour RAL 7031 and screws and washer are in stainless steel; the protection level of the device is IP 55 and of the contacts IP 67. Therefore the device is suitable for fitting in the open even in tropical climate and with high industrial pollution.

3.3 Accessories

The device is supplied with its assembly gasket and with one cable entry fitted with a metallic plug.


4.1 Wiring diagrams In the following table are shown all the standard wiring diagrams (special wiring diagrams are provided on demand)


WD = Wiring diagram code N° Term. = Numbers that identify the terminals Pos. in NE = State of the contact in normal exercise. Corresponds to maximum flow.

4.2 Contact's Performance 4.2.1 Standard Contact (ST)

Changeover micro switch contact worked mechanically Degree of protection IP 67 Casing Poliester Gasket Fluorosilicon rubber Lever and push button Stainless steel Contact's material Silver, nickel coated Mechanical endurance of contact 1x10

7 cycles

Temperature range -40°C to +125°C Standard power of interruption (1x10

5 cycles) AC 250V/5A - DC 125V/1A

Maximum power of interruption (1.000 cycles) DC 125V/1,5A

Isolation to mass at 20°C 2.500 V Isolation of open contact at 20°C 1.500 V Minimum and maximum current 0,1 - 10A

4.2.2 Low Current Contact (BC) Same performance as standard contact except: Contact's material Gold Operation range 1 to 100 mA - 4 to 30 V

4.2.3 Electric circuitry Degree of protection of instrument casing IP 55 Insulation to mass 2.500 V Material of terminal board Tin coated brass

5 Operation

The circulation indicators Series CCL2 operate as follows:

• the fluid moving in the pipe hits the paddle 3.1, which has dimensions chosen according to pipe di-ameter and nominal fluid velocity, and causes it to rotate around its axis 3.1.1 by about 22°; the movement of the paddle is limited by the stops 3.2.2, which act on the pin 3.2.1;

WD N°

Term. Pos. in NE

Functional description of wiring diagram Operates at

00 Without contacts, only optical indication

F0 1-2 Open

1 changeover contact for minimum flow minimum 1-3 Closed

G0 1-2 Open

1 changeover contact for maximum flow maximum 1-3 Closed

AA 1-2/4-5 Open 2 contacts for minimum flow minimum

BB 1-3/4-6 Closed

DD 1-2/4-5 Open 2 contacts for maximum flow maximum

EE 1-3/4-6 Closed

FG

1-2 Open 1 changeover contact for minimum flow minimum

1-3 Closed

4-5 Open 1 changeover contact for maximum flow maximum

4-6 Closed


• the movement of the paddle provokes the rotation of the shaft 3.2 and thus the lever 3.3 by means of the pin 3.2.1, winning over the force of the return spring 3.5;

• lever 3.3 triggers the electric signal through microswitches 3.7 while the two red and white displays 3.3.1, fitted to the lever itself, move in front of the sight glasses 2.2, showing either the red or white sector, respectively when the flow rate is lower or higher than the pre-set value; as already men-tioned, the optical display may not be proportional to the flow rate;

• when the fluid velocity falls below the pre-set value, the return spring 3.5 brings the mechanism into its rest position.


6.1 Mounting

The circulation indicators Series CCL2 may be used when the working conditions are wihin the values indicated in chapter 1.2.

The device is either mounted on a flange with stub pipe, welded directly to the pipe following the dimen-sions indicated in the table of drawing CCL2 – GENERAL OVERWIEW, or by mounting a flanged stub pipe onto the pipeline, sectioned off by valves, and attaching the device to it as indicated in the as-sembly example of drawing CCL2 – GENERAL OVERWIEW. It is best to choose this second method if the device will need to be removed for maintenance, as may be necessary if it is used with water.

The device is mounted using M8 bolts, with the insertion of the assembly gasket supplied with the de-vice. After attaching it to the pipe, carry out the electrical connection according to the chosen wiring dia-gram through the terminal board 3.7, accessible after removing the cover 2.1. After mounting, verify that the optical and electric indicators are working correctly by starting up and stopping the circulation pump.

In order to make sure the signal paddle 3.1 is hit by the most uniform possible flow, avoid mounting the device immediately down stream of bends, necks or other parts which could cause turbulence in the flow; if this is impossible, the adjustment of the tension in the return spring 3.5, allows the indicator to be set to the real flow conditions

6.2 Adjustment

The device is always supplied set according to the information given at ordering and with the adjustment spring 3.5 loaded to about half the maximum load, so that it is possible to both increase the load, so the device is triggered at a higher flow rate, or decrease the load, with the opposite effect. To make adjust-ments of spring 3.5 proceed as follows:

• remove cover 2.1;

• insert a hollow barrel spanner inside on the hexagonal adjuster 3.6;

• insert a screwdriver inside the barrel spanner and unscrew the adjustment locking screw by about one turn;

• turn the hexagonal adjuster in anticlockwise direction to increase the operational flow rate and in clockwise direction to decrease it; the maximum angle the hexagonal adjuster can be rotated is about 90°; two lockpins prevent it from being turned beyond this angle;

• lock the hexagon 3.6 in the new position by tightening the locking screw;

• verify that the device is working correctly by starting up and stopping the circulation pump.

• replace cover 2.1.

6.3 Maintenance

The circulation indicators Series CCL2 do not need regular maintenance, however it is advisable to check that they are working correctly at regular intervals by starting up and stopping the circulation pump and verifying that the optical and electrical display takes place as normal.

As mentioned above, it is possible that if used with water deposits and encrustation's may form which prevent the device from working correctly. In this case remove the device from the pipe - closing any shutoff valves present or emptying the installation - and carry out cleaning by removing protection 1.1 and eliminate the encrustation's mechanically until the paddle moves freely once again.


7 Order Specifications

When ordering it is necessary to indicate the following data:

• type of device:

◊ CCL2-O for use with transformer oil;

◊ CCL2-A for use with water;

• pipeline diameter;

• mounting position according to drawing CCL2 – GENERAL OVERWIEW;

• flow rate at which the indicator should be triggered;

• wiring diagram;

• thread of cable entries.

8 Part denomination of drawing CCL2 – CROSS SECTION

Pos. Part denomination N° Material

1.0 Body with flow direction indication 1 CCL2-O - Aluminium CCL2-A - Brass

1.0.1

Mounting flange: Types CCL2-O and CCL2-A with O-Ring gasket groove for OR 6262 Types CCL2-OS and CCL2-AS without O-Ring gasket groove

1

1.1 Protection 1 Brass

2.0 Casing 1 Aluminium

2.0.1 Cable entry - Max 1" or PG21 2

2.1 Casing cover 1 Aluminium

2.2 Window of optical indication 2 Acrylic

2.3 Window frame 2 Nylon 30% glass fibre

2.4 Wiring diagram and serial number plate 1 Aluminium serigraph.

2.5 Cover fixing string 1 Nylon

3.0 Optical and electrical indication unit

3.1 Flow measuring disk paddle 1 CCL2-O - Aluminium CCL2-A - Brass

3.1.1 Disk paddle axis 1 Stainless steel

3.2 Transmission shaft 1 Stainless steel

3.2.1 Transmission shaft pin 1 Stainless steel

3.2.2 Transmission shaft stops 2 Stainless steel

3.3 Lever of optical and electrical indication 1 Brass

3.3.1 Dials of optical indication 2 Aluminium serigraph.

3.4 Microswitches 1/2

3.5 Reset spring 1 Spring steel

3.6 Regulation knob 1 Brass

3.7 Terminal board for electrical connection 1

3.8 Earthing screw 1 Stainless steel

Nome file : RT6

1.0 Features

When it is required to limit the pressure rise inside a tank, in order to prevent an excessive mechanical stress of the walls, it is necessary to use a safety valve set at a precise The tank of oil-immersed transformers is usually fit with this kind of protecting device; as matter of fact, in case of short-circuit due to an insulation failure, the dielectric arc between alive parts vaporises the surrounding insulating fluid which generates a quick rise of the pressure inside the tank, with the risk of permanent deformations, or, even, of the failure of the tank walls with the consequent flowoil. Due to the high rapidity of this event, it is necessprotecting device which relieves quite suddenly the excess of pressure generated inside the tank by the above mentioned failure. Our Pressure Relief device RT6 can assure such kind of protection

2.0 Construction features Reference drawings

Assembly, overall dimensions, available wiring diagram, and cross section: see drawing 1375Materials and components

Flange is made in aluminium alloy pressure die castedsprings (compression type) are made of special hardened spring steel; gaskets (in standard execution) in NBR; fittings in stainless steel or

Surface protection Flange, cover and contact’s casing are painted internally and externally with one primpaint and externally with a finishing powder coating colour RAL7030. The primer coat on the internal surfaces in contact is compatible with transformer mineral oil up to temperatures of 120°C. Total thickness of the two coats is 120 micronlocated in very polluted areas; springs other parts made in brass are

Construction The pressure relief valve type RT6mounting flange with the central opening closed by a spring loaded shutter; the springs are compressed between shutter and the protective cover (that has also the function of compressive riwhich is assembled to the flange by columns. No one part of the pressure relief valve A specially designed set of gasket assures the oilis in closed position.

Operation indication A red armed semaphore, horizontally locked in rest position, rotatesthe top of the valve cover, in case of The operation of the pressure relief valve is alsocharacteristics at paragraph 5)

Oil-tightness and resistance to pressureThe pressure relief valve RT6 table at end of paragraph 6), which dMechanically, the pressure relief valve are resistant to vacuum (10 torr) and to internal pressure4 bars.

Resistance to dynamical stressThe pressure relief valve RT6 Sinus vibrations with frequency <= 120 Hz and amplitude <= 250 µ;Dynamic conditions causing following accelerations: - Max 3g in all directions, sinus vibration, amplitude <= 20 mm; - Shock condition with max 10 g in all directions.

UNCONTROLLED COPY

When it is required to limit the pressure rise inside a tank, in order to prevent an excessive mechanical stress of the walls, it is necessary to use a safety valve set at a precise overpressure value.

immersed transformers is usually fit with this kind of protecting device; as matter of fact, circuit due to an insulation failure, the dielectric arc between alive parts vaporises the

insulating fluid which generates a quick rise of the pressure inside the tank, with the risk of permanent deformations, or, even, of the failure of the tank walls with the consequent flow

rapidity of this event, it is necessary to mount on the transformer an adequate protecting device which relieves quite suddenly the excess of pressure generated inside the tank by the

Our Pressure Relief device RT6 can assure such kind of protection

Assembly, overall dimensions, available wiring diagram, and cross section: see drawing 1375Materials and components

made in aluminium alloy pressure die casted; shutter in stainless steelompression type) are made of special hardened spring steel; gaskets (in standard execution)

stainless steel or brass or mild steel

Flange, cover and contact’s casing are painted internally and externally with one primpaint and externally with a finishing powder coating colour RAL7030. The primer coat on the internal surfaces in contact is compatible with transformer mineral oil up to temperatures of 120°C. Total

two coats is 120 microns; special painting cycle can be provided for transformer located in very polluted areas; springs and fittings made in mild steel are epoxy coated

are nickel plated

essure relief valve type RT6 is an out of tank spring loaded safety valve, consisting of a mounting flange with the central opening closed by a spring loaded shutter; the springs are

etween shutter and the protective cover (that has also the function of compressive riwhich is assembled to the flange by columns.

part of the pressure relief valve protrudes inside the transformer tank. gasket assures the oil-tightness between flange and shutter when the valve

A red armed semaphore, horizontally locked in rest position, rotates up, showing approx 50 mm over the top of the valve cover, in case of valve operation due to an overpressure. The operation of the pressure relief valve is also indicated by one or two electric contactcharacteristics at paragraph 5).

tightness and resistance to pressure e pressure relief valve RT6 are oil tight with oil at 100°C up to the tightness test pressure Pt

, which depends on the setting pressure , the pressure relief valve are resistant to vacuum (10 torr) and to internal pressure

Resistance to dynamical stress can operate without undue operation in the following conditions:

Sinus vibrations with frequency <= 120 Hz and amplitude <= 250 µ; conditions causing following accelerations:

Max 3g in all directions, sinus vibration, amplitude <= 20 mm; Shock condition with max 10 g in all directions.

rev. 02 dtd 09/09/08

When it is required to limit the pressure rise inside a tank, in order to prevent an excessive mechanical overpressure value.

immersed transformers is usually fit with this kind of protecting device; as matter of fact, circuit due to an insulation failure, the dielectric arc between alive parts vaporises the

insulating fluid which generates a quick rise of the pressure inside the tank, with the risk of permanent deformations, or, even, of the failure of the tank walls with the consequent flow-out of hot

ary to mount on the transformer an adequate protecting device which relieves quite suddenly the excess of pressure generated inside the tank by the

Assembly, overall dimensions, available wiring diagram, and cross section: see drawing 1375

in stainless steel; cover in mild steel; ompression type) are made of special hardened spring steel; gaskets (in standard execution)

Flange, cover and contact’s casing are painted internally and externally with one primer coat of epoxy paint and externally with a finishing powder coating colour RAL7030. The primer coat on the internal surfaces in contact is compatible with transformer mineral oil up to temperatures of 120°C. Total

s; special painting cycle can be provided for transformer epoxy coated protected and

safety valve, consisting of a 6 holes mounting flange with the central opening closed by a spring loaded shutter; the springs are

etween shutter and the protective cover (that has also the function of compressive ring),

tightness between flange and shutter when the valve

showing approx 50 mm over .

indicated by one or two electric contacts (see the

tightness test pressure Pt (ref

, the pressure relief valve are resistant to vacuum (10 torr) and to internal pressure up to

following conditions:

Nome file : RT6

3.0 Operation and installationOperation

Should an overpressure inside the transformer tank rise up, higher than the operation pressure set, the shutter of the relief valve lifts slowly from the rest positiexcess of gas can’t be released yet from valve due to the second tightening gasket which is still in contact with the shutter; in this position, the gas (or the oil) is operating over a much bigger area than the surface defined by the main gasket; the result is that in few milliseconds there is a very high increase of the load on the shutter which winthe excess of pressure is released very quickly throughwhich, after it, recloses as much suddenly as its opening.

Importance of the electric contactReal life tests have shown, that failures of the transformer followed by sudden pressure increases, such as for instance short circuits, induce the operation of the pressure relief valve in time spans which are considerably shorter than that of other safety devices, such as the Buchholz Relay.

Installation There is not any precise formula to be used totransformer. The normal practice suggests to use one pressure relief device for each 35.000 litres of transformer oil capacity or fraction.The pressure relief valve should be installed, either in horizontal or vertical posittank or cover, as near as possible to the failure sources or in a central position to such sources making sure of a good visibility of the red semaphore

4.0 Setting The setting of the pressure relief valve RT6pressure value; therefore the setting of the pressure relief valve can be changed only at the factory, thus eliminating possible misuses.The performance of the pressure relief valves depends from the test fluid and the transformer tank. The pressure values listed below are obtained by operating the valves with compressed air on a test bed having a compressed air volume of 150 dmTo avoid oil leakage or undue operation of the valve, the operating pressure normal operation the corresponding maximum operating pressure is never reached.In following table are indicated the tolerance of the closing pressure and the tightness pressure

Pn

[bar] [kPa] -

0,35 35

0,42 42

0,49 49

0,56 56

0,7 70

0,84 84

Pn (nominal pressure) is the setting pressure of the pressure relief valve, on which the tolerance must be applied in order to determinate the minimum and maximum operating pressure.Pmin, Pmax (minimum and maximum operating pressure) are the limits of the pressure range inside which the pressure relief valve must operate.Pc (closing pressure) is the minimum pressure at which the valve closes after operationPt (tightness test pressure) is the pressure at which the valve if tested during the leakage tests.

UNCONTROLLED COPY

Operation and installation

Should an overpressure inside the transformer tank rise up, higher than the operation pressure set, the of the relief valve lifts slowly from the rest position disjoining the main tightening gasket; the

excess of gas can’t be released yet from valve due to the second tightening gasket which is still in contact with the shutter; in this position, the gas (or the oil) is operating over a much bigger area than

e surface defined by the main gasket; the result is that in few milliseconds there is a very high increase of the load on the shutter which wins the springs counterload and the shutter lifts suddenly; the excess of pressure is released very quickly through the very big section opened by the shutter

recloses as much suddenly as its opening. Importance of the electric contact

Real life tests have shown, that failures of the transformer followed by sudden pressure increases, ce short circuits, induce the operation of the pressure relief valve in time spans which

are considerably shorter than that of other safety devices, such as the Buchholz Relay.

y precise formula to be used to determine the nr of valve to be installed on one transformer. The normal practice suggests to use one pressure relief device for each 35.000 litres of transformer oil capacity or fraction. The pressure relief valve should be installed, either in horizontal or vertical posit

, as near as possible to the failure sources or in a central position to such sources making visibility of the red semaphore.

he pressure relief valve RT6 is effected by choosing a proper spring for every operating pressure value; therefore the setting of the pressure relief valve can be changed only at the factory, thus eliminating possible misuses. The performance of the pressure relief valves depends from the test fluid and the transformer tank. The pressure values listed below are obtained by operating the valves with compressed air on a test bed having a compressed air volume of 150 dm

3.

To avoid oil leakage or undue operation of the valve, the operating pressure must be chosen so that in normal operation the corresponding maximum operating pressure is never reached.In following table are indicated the tolerance of the standard pressure setting, the service pressure, the closing pressure and the tightness pressure for the different nominal pressure settings.

Pmin Pmax Pc

- % [bar] + % [bar] [bar]

20 0,28 20 0,42 0,12

17 0,35 17 0,49 0,14

14 0,42 14 0,56 0,18

12 0,49 12 0,63 0,22

10 0,63 10 0,77 0,28

8 0,77 8 0,91 0,35

(nominal pressure) is the setting pressure of the pressure relief valve, on which the tolerance must be applied in order to determinate the minimum and maximum operating pressure.

(minimum and maximum operating pressure) are the limits of the pressure range inside which the pressure relief valve must operate.

(closing pressure) is the minimum pressure at which the valve closes after operationthe pressure at which the valve if tested during the leakage tests.

rev. 02 dtd 09/09/08

Should an overpressure inside the transformer tank rise up, higher than the operation pressure set, the on disjoining the main tightening gasket; the

excess of gas can’t be released yet from valve due to the second tightening gasket which is still in contact with the shutter; in this position, the gas (or the oil) is operating over a much bigger area than

e surface defined by the main gasket; the result is that in few milliseconds there is a very high the springs counterload and the shutter lifts suddenly;

g section opened by the shutter

Real life tests have shown, that failures of the transformer followed by sudden pressure increases, ce short circuits, induce the operation of the pressure relief valve in time spans which

are considerably shorter than that of other safety devices, such as the Buchholz Relay.

f valve to be installed on one transformer. The normal practice suggests to use one pressure relief device for each 35.000 litres of

The pressure relief valve should be installed, either in horizontal or vertical position, on the transformer , as near as possible to the failure sources or in a central position to such sources making

spring for every operating pressure value; therefore the setting of the pressure relief valve can be changed only at the factory,

The performance of the pressure relief valves depends from the test fluid and the layout of the transformer tank. The pressure values listed below are obtained by operating the valves with

must be chosen so that in normal operation the corresponding maximum operating pressure is never reached.

pressure setting, the service pressure, the for the different nominal pressure settings.

Pt

[bar]

0,26

0,31

0,36

0,42

0,52

0,63

(nominal pressure) is the setting pressure of the pressure relief valve, on which the tolerance must be applied in order to determinate the minimum and maximum operating pressure.

(minimum and maximum operating pressure) are the limits of the pressure range inside

(closing pressure) is the minimum pressure at which the valve closes after operation the pressure at which the valve if tested during the leakage tests.

Nome file : RT6

5.0 Electric contacts The contacts used are microswitchthe contacts remain in trip position and it is necessary to reset them manually by rotating the red semaphore (located on the cover of the PRD) in terminal box made of aluminium with a cable

Characteristic of N/O and N/C contacts (used in wiring diagram C1 and C2)Type Lever Contact material Mechanical life of contact Temperature range Standard interruption power Insulation to earth at 20°C Insulation of open contact at 20°CProtection degree of terminal box

Characteristic of changeover Type Lever Contact material Mechanical life of contact Temperature range Standard interruption power Insulation to earth at 20°C Insulation of open contact at 20°CProtection degree of terminal box

6.0 Compatibility of installation

The installation compatibility of the pressure relief valve the gaskets; our standard material is high quality NBRambient conditions) therefore aEnvironmental conditions. Ambient temperature: -20°C to +50°CRelative humidity: 95% at 20°CInsulating liquid (transformer mineral or silicon oilTemperature: -20°C to + 110°CFor other environmental and/or operating conditions to be examined individually.

7.0 Ordering Instructions When ordering must be defined follow - Model of pressure relief device : RT6

- Wiring diagram (ref to drawing 1375) : CX; C1; C2- Nominal operating pressure in kPa (or bar or psi)- Special requirements Example Nr 1 Pressure relief device type Means that is required nr 1 PRD type RT6 having 2 contacts 1 N/O and 1 N/C (wiring diagram C1)nominal pressure 0.5 bar, standard execution

UNCONTROLLED COPY

contacts used are microswitch type and are mechanically operated by the shutter; after operation the contacts remain in trip position and it is necessary to reset them manually by rotating the red semaphore (located on the cover of the PRD) in the rest position; the contacts are houseterminal box made of aluminium with a cable gland or conduit entry M25

N/O and N/C contacts (used in wiring diagram C1 and C2)Limit switch Stainless steel Silver 2x10

7 cycles

-40°C - +125°C AC 125/250V-5A - DC 125V-2A 2.500V

Insulation of open contact at 20°C 1.500V gree of terminal box IP 67

changeover contacts (used in wiring CX) Microswitch Stainless steel Nickel coated silver 1x10

7 cyles

-40°C - +125°C AC 125/250V-15A - DC 125V-1A 2.500V

Insulation of open contact at 20°C 1.500V of terminal box IP 65

Compatibility of installation The installation compatibility of the pressure relief valve RT6 depends mainly on the material used for

our standard material is high quality NBR (which is compatible admitted operating conditions are:

20°C to +50°C 20°C - 80% at 40°C - 50% at 50°C

transformer mineral or silicon oil). 20°C to + 110°C

For other environmental and/or operating conditions to be examined individually.

When ordering must be defined following data: ressure relief device : RT6

ing diagram (ref to drawing 1375) : CX; C1; C2 in kPa (or bar or psi)

Nr 1 Pressure relief device type RT6 C1 0.5 bar PRD type RT6 having 2 contacts 1 N/O and 1 N/C (wiring diagram C1)

standard execution

rev. 02 dtd 09/09/08

type and are mechanically operated by the shutter; after operation the contacts remain in trip position and it is necessary to reset them manually by rotating the red

contacts are housed inside the

N/O and N/C contacts (used in wiring diagram C1 and C2)

mainly on the material used for with the most common

For other environmental and/or operating conditions to be examined individually.

PRD type RT6 having 2 contacts 1 N/O and 1 N/C (wiring diagram C1), set at

Documents

THERMOMETERS FOR POWER TRANSFORMERS …maxsteel.sg/.../accessories_for_power_transformers.pdf · File : OTI-WTI ing UNCONTROLLED COPY Rev. 3 dtd 10/10/08 THERMOMETERS FOR POWER TRANSFORMERS