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What is the primary function of the protective relay in the system?
Which section is most likely to provide guidelines for the proper installation of the protective relay?
What is the minimum oil flow required to trip the valve at 20°C for on-load tap-changers of Type E, F, G, K, R, T, G?
What kind of alterations does the manufacturer reserve the right to make?
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Which feature of the housing ensures that water condensation is prevented in the terminal box?
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What voltage is required to test the relay's insulation to earth?
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Which section likely details operational guidelines post installation?
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In terms of technical specifications, which aspect of the protective relay is crucial for ensuring its effectiveness?
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What additional feature must a protective relay have when connected to the transformer?
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What is most likely included in the 'Electrical connection' section?
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What material is used for the housing of the relay?
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How many change-over contacts does the tripping switch contain?
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Which information is likely to be found in the Appendix?
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What is a potential design feature of the protective relay that aids in maintenance?
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What is the degree of protection rating for the housing of the relay?
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What purpose do the two inspection glasses on the housing serve?
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What is the protection type used for the protective relay (Ex)?
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Which temperature classes are applicable for the protective relay on business premises subject to explosion hazards?
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Which standard does the protective relay (Ex) comply with?
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What is a potential application area for the protective relay (Ex)?
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Which of the following is NOT a design feature of the protective relay (Ex)?
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In which year was the protective relay documentation printed, according to the content?
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The protective relay must be tested again after energization before putting the transformer into service.
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The maximum torque for connecting the leads to the terminal bolts is 10 Nm.
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It is advised to vent the protective relay when the transformer is filled with oil.
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When the flap valve is not in the 'Transformer off' position, the tripping circuit requires examination.
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The hood and terminal box cover of the protective relay should be locked using 3 screws.
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The tap changer insert should be put back into service immediately after inspection.
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The maximum torque for locking the hood is 7.5 Nm.
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Circuit breakers must allow the transformer to be switched on without pressing the protective relay's reset button.
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The primary function of the protective relay is to ensure compliance with environmental regulations.
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Installation guidelines are included in the section labeled 'Putting into Operation'.
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Protective relays are designed to operate effectively at temperatures above 50°C.
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The design of the protective relay includes features to facilitate easy maintenance.
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The appendix section offers specific information about warranty conditions.
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Modifications to the protective relay can occur without prior notice to the customer.
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The electrical connection section provides guidelines solely for safety-related wiring.
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Protective relays are only compatible with specific models of transformers and tap changers.
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The pipes from the protective relay to the oil conservator should have a nominal width of 30 mm to ensure proper operation.
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A protective relay should be installed in a vertical position to avoid erroneous responses from the mercury contact tube.
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The test push buttons of the protective relay must be located at the bottom of the housing.
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A stop valve is recommended to be installed between the protective relay and the oil conservator for safety.
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The tripping switch of the protective relay can only be connected as normally closed (n/c).
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To allow free escape of switching gas, the pipes connecting the protective relay should be inclined at 3 to 4 percent.
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For the protective relay to function effectively, it should not be exposed to transformer vibrations.
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The location of the arrow on the housing indicates the direction towards the transformer.
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Study Notes
General Information
- Protective relay prevents damage to tap changers and transformers, included in delivery.
- Connection must ensure immediate transformer shutdown when the relay is energized.
Technical Data
- Outdoor housing design with IP 44 protection degree.
- Relay control via flap valve with two drill hole sizes: 10 mm and 20 mm.
- Compatible on-load tap-changers: Type A, M, V, H and Type E, F, G, K, R, T, G.
- Minimum oil flow for tripping the valve at 20°C: at least 1.0 m/s for valve size 10 mm and 2.4 m/s for size 20 mm.
- Tripping switch uses a mercury switching tube with one change-over contact.
- Inrush and breaking current rating: 24...220 V a.c. and d.c., 2 amps (L/R = 25 ms).
- Test voltage to earth requirement: 2.5 kV, 50 Hz, for 1 minute.
- Weight is approximately 5 kg.
Design Features
- Housing made from non-corrosive light alloy with two flanges for pipe connections.
- Flap valve position is visible through two inspection glasses located on the front and rear.
- Tripping switch terminals housed in a terminal box, protected against oil.
- Breather in terminal box helps prevent water condensation.
- Flap valve diameter is labeled over the terminal box.
- Two push buttons for checking tripping function and resetting the flap valve are covered by a hood.
Special Designs
- Protective Relay 1000 (Ex) available upon request at an additional cost.
- Complies with VDE 0171/1.69 for explosion protection, suited for hazardous business environments.
- Suitable for temperature classes G1 and G4, applicable to flammable materials.
Appendix
- Includes dimension drawing for Protective Relay RS 1000 (document code 8995660E).
Cable Gland Installation
- Fit the cable gland for leads with a diameter of 8 to 13 mm.
- Close unused bore with a blind cover.
- Connect leads to terminal bolts M5 with a maximum torque of 2 Nm.
- Connect protective conductor to screw M6 (torque max. 5 Nm).
- Lock hood and terminal box cover using 2 screws (wrench opening 13, max. torque 8.5 Nm).
- Venting of the protective relay is unnecessary while transformer is filled with oil.
Putting into Operation
- Test the protective relay again according to section 5.1 before putting transformer into service.
- Ensure circuit breakers trip transformer upon pressing "Trip" button.
- Confirm transformers can only be restarted after the "Reset" button is activated.
- Lock screws of terminal box cover and push button hood can be sealed.
Energization of the Protective Relay
- Determine energization time and tap changer operating position.
- Check flap valve position; if not "Transformer off," examine the tripping circuit.
- Remove tap changer insert for inspection as per instructions before reactivation.
- Notify manufacturer or authorized rep if oil flow has affected flap valve position.
General and Technical Data
- Protective relay prevents damage to tap changer and transformer.
- Test push buttons must be positioned for correct operation; "Transformer off" connects terminals 1 and 3, while "Transformer in operation" connects terminals 1 and 2.
- Flap valve position must be monitored; improper installation may affect relay accuracy.
- Ensure pipes to tap changer and oil conservator are 25 mm width, with a 1-2% incline for gas escape.
- Install relay to mitigate transformer vibrations; include a stop valve between relay and oil conservator.
Electrical Connection
- Tripping switch can be configured as normally open (n/o) or normally closed (n/c).
- Energization of the relay should immediately trip transformer circuit breakers.
- Use threaded bore in terminal box for entering leads, selecting the most suitable side.
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Description
This quiz covers the technical specifications and design features of protective relays used in tap changers and transformers. Explore the important parameters such as housing design, valve control, and specific compatible tap-changer types. Test your knowledge on the proper functioning and requirements of these essential electrical components.
