Monitoring Relay for Tap Changers

7/28/2019 Monitoring Relay for Tap Changers

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Elektromotoren undGertebau Barleben GmbH

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Monitoring relayfor tap changers


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Firms history

Since its foundation the company has beenpassed through an eventful history with regardto ownership, affiliation and connected with thischanges of firm names.

1863 Foundation of the companyas sugar factory

1943 Establishment of SIEMENSMagdeburg

1948 VEB1 Elektromotorenwerk

Barleben; VEM(state-owned firm)

1951 VEB1 StarkstromanlagenbauMagdeburg(state-owned firm)

1951 Start of manufacturingBuchholz relays at sitein Barleben

1965 Start of manufacturingMonitoring relays for

tap changers at sitein Barleben

1970 VEB1 Elektrotechnik undGertebau Magdeburg;EGEM(state-owned firm)

1980 VEB1 KombinatElektromaschinenbau DresdenVEB1 ElektromotorenwerkBarleben; VEM; ELMO(state-owned firm)

1990 VEM Antriebstechnik AGDresdenElektromotorenwerk BarlebenGmbH; VEM; ELMO(public limited company)

1993 Elektromotoren undGertebau Barleben GmbH;EMB(privately owned company)

Preface

The Monitoring relay for tap changers, also namedprotection relay for tap changers or oil flow relay, is amonitoring relay for oil-insulated tap changers. It protectsthe tap changer and the transformer from damage. Onresponse the monitoring relay will generate a signaldisconnecting immediately the tap changer and thetransformer from the source of supply.

The company has had for more than 40 years experiencein producing Monitoring relays and other protectiondevices for liquid-cooled appliances. It ranks among themost distinguished manufacturers of this kind ofequipment.Experiences collected and profound know-how are thesound basis for a high product quality. References fromreputed transformer and tap changer manufacturers aswell as further users are proof of the high level of theproducts.The company is DIN EN ISO 9001/2000 certified.

The staff of highly qualified engineers and experiencedskilled workers do their best to guarantee top qualityhigh-precision products..The mechanical working of the casings is done on

modern CNC-controlled machine tools. The final tests,where all the functions of the Monitoring relays arechecked, are done with each device by using special testequipment.Each device is delivered with a test certificate.

Monitoring relays may be used in open-air or also inindoor equipment.

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1 VEB = nationally owned firm


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1. Design features

Casing (Figure 1)

The casing is a weather-resistantcasting of light alloy and is provided

with a paint coat.To check the switching system forproper function, the casing isprovided with inspection glassesarranged opposite each other,protected by hinged lids (1).

Figure 1 : casing

Figure 2 : cover with dismantled cap (Thepicture shows the identif.no. 25 oftable 2.)

Cover (Figure 2)

The cover is a weather-resistant casting of lightalloy and is provided with a paint coat. Terminalbox, test and reset button (1), covered by a cap nutas well as a bleeder screw (2) are arranged abovethe cover. The terminal box has an earthingcontact (3) and the electrical connectors (4).By means of a removable cap (5) the terminal boxis safe to touch and protected against pollution.The cable is to be brought in the terminal box

through the cable gland (6).

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6

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Switchgear (Figure 3)

The switchgear has the following main components:Switching system

Carrier, frameMechanical testing device.

The switching system consists of thefollowing components:

damper (1)switching magnet(s) (2)magnet contact tube(s) (3)

Figure 3 : switchgear (The picture shows theidentif.no. 25 of table 2.)

The damper is retained in its normal and response positions by permanent magnets. Via a link the

switching magnet is firmly connected with the damper and initiates the contact-making process of themagnet contact tube at a certain oil flow.

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2. FunctionThe Monitoring relay has to be mounted into the pipe leading from the tap changer head to the oilconservator located as near as possible to the tap changer head.Due to the working method of the tap changer there is gas inside the gas collecting dom of the device.In case of oil flow the Monitoring relay responds as follows:Fault : An incident generates an oil flow in the direction

of the conservator.Response: The liquid flow reaches the damper arranged inthe liquid flow. If the flow rate exceeds the operatingthreshold of the damper, the latter moves in flow direction.Due to this movement a switch contact is actuated.For that the tap changer and the transformer aredisconnected.

Figure :4 : principle of workingmethod of the damper

3. Technical data

Table 1Parameter Data Notes

Nominal voltage AC 230 VDC 230 V

12 V to 250 V12 V to 250 V

Nominal current AC 2 ADC 2 A

0.05 A to 2 A0.05 A to 2 A

Contact voltage capacity AC 1000 V --Insulation voltage capacity AC 2000 V Contact against casingTemperature range:- ambient temperature

- working range

* temperature of the insulation liquid

* viscosity of the insulation liquid

-45oC to +55o C-49o F to +131o F

-25o

C to +115o

C-13o F to +239o F1 mm2/s to 1100 mm2/s

Others on request

Others on request

Others on requestSwitching system:- Switching contact

- damperResponse time of damperResponse values of the damper

magnet contact tube

hold by magnets< 0.1 s0.9 m/s 2.0 m/s1.0 m/s 2.5 m/s1.2 m/s 3.0 m/s1.5 m/s 4.0 m/s

normally-open, normally-closed,change-over

Others on request

Resistance to pressure 0.25 MPa --

Resistance to vacuum < 2.5 kPa --Cable gland M 20x1.5 Others on requestDegree of protection IP 54 Others on requestNominal installation position 2 o ascending towards

expansion vessel2 to 4 o

4. Special designs

Table 2Explanation Identif.no.

Climatic version (suited for tropical open-air climates) 22

Climatic version (suited for extrem frigidal open-air climates below 45 C) 34Special design approved by RWE, Germany (formerly RF 25/10-3) 24Switching system equipped with two magnet contact tubes (formerly RF 25/10-2) 25Customer request on the basis of conditions agreed with the manufacturer 29

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5.Types and Dimensional sketches5.1. Type 12

RF 25/10

5.2. Type 15

RF 25

6. Ordering data

For placing orders, please, use the following key :

XX X X. . . XXXX . Contact setting ofswitching system

Important remark:NO = normally-openNC = normally-closed

1 = 0,9 m/s2 = 1,0 m/s

3 = 1,2 m/s4 = 1,5 m/s5 = 2,0 m/s6 = 2,5 m/s7 = 3,0 m/s8 = 4,0 m/s9 = special agreement

with the customer

Damper setting

Special design

(see table 2)

Type code no.(see para.5)

1 = one NO-contact2 = one NC-contact3 = one change-over contact4 = two NO-contacts

5 = two NC-contacts6 = one NO-contact and one NC-contact

7 = two change-over contacts8 = one NO-contact and one change-

over contact9 = one NC-contact and one change-

over contact

Ordering example:Monitoring relay RF 25/10 12-22.25.-56

Explanation: 12 = RF 25/10 22 = climatic version25 = switching system equipped with

2 magnet contact tubes5 = damper setting of 2.0 m/s6 = contact setting of the switching

system 1 NO-contact and 1 NC-contact

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7. Tests

To each Monitoring relay a works-number is given mentioned in the test certificate.Furthermore the tests made with the Monitoring relay are documented in the test certificate:

- Dielectric strength test(AC 2000 V against casing)

- Leakage test(25 min with80o C warm transformer oil at 0.25 MPa)

- Functional test(damper setting) .

With each device we deliver

- operating instructions

The Monitoring relays are delivered in transportcardboards.

- test certificate

in the desired language.DIN EN ISO 9001:2000 certificate

Flow test Functional and leakage test

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8. Further products

Elektromotoren und Gertebau Barleben GmbH may supply also products for protection andsupervision of liquid-insulated transformers and choke coils.

Please, ask for our separate catalogues.

Designation Description

BR

NEW

Buchholz relaysTransformer protection relays (Buchholz principle)

NM series Buchholz relays with analog measurement of the gas volume

ZG 1.2. Gas sampling deviceThe device is mounted at the transformer and connected to the Buchholz relay by

means of a pipe. It allows to sample the relay gas at normal operating level.The device can be delivered with a lockable box.

ZG 3.1. Gas testing deviceThe device serves to analyze the relay gas by means of two test fluids. It can bemounted directly on the Buchholz relay as well as on the Gas sampling deviceZG 1.2.

ZG 4.1. Reflux lockThe device prevents that the insulation liquid gets into the Gas testing device.

ZG 5.1.ZG 5.2.

Test pumpThe device serves to check the upper switching system by means of air.

- manual-actuated

- foot-actuated

ZG 6.1.

Oil sampling deviceThe device is connected to the Buchholz relay by means of a pipe and serves totake oil samples (can be used for Buchholz relays with oil drain plug).

BGS Buchholz gas samplerThe Buchholz gas sampler can be connected to the Buchholz relay or to the Gassampling device. It serves to sample and to transport safe the gas.

BGT Buchholz gas testerThe Buchholz gas tester serves to analyze the Buchholz gas regarding thehydrogen concentration.

SG 25SF 25

Oil flow indicator- with thread connection- with flange connection

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Bahnhofstrae 27/28

39179 Barleben / Germany

Phone: +49 39203 790

Telefax: +49 39203 5330

Telefax: +49 39203 5450

E-Mail: [email protected]: http://www.emb-online.de

Edition: Catalogue Monitoring relays 01 / 05 English

Due to technical improvement of our products, the information contained in this brochure may besubjected to change without notice.

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mailto:[email protected]:[email protected]

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Monitoring Relay for Tap Changers