Protective Relays Quiz

Protective relays are the devices that detect abnormal conditions in electrical circuits by measuring

• Voltage

• Current

• Constantly the electrical quantities which differ during normal and abnormal conditions

• Note the above

Buchholz relay is

• Located in the conservator tank

• Located in the transformer tank itself

• Connected in the pipe connecting main tank of transformer and conservator

• Installed in the circuit breaker

The protective relays is provided to

• Provide additional safety to the circuit breaker in its operation

• Close the contacts when the actuating quantity attains a certain predetermined value

• Limit the arcing current during the circuit breaker operation

• Earth any stray voltage

For the protection of a very long extra high-voltage lines, the productive relay used is

• Over currently with extremely inverse characteristics

• Percentage differential relay

• Reactance type distance relay

• Mho type distance relay

Burden of a protective relay is the power

• Required to operate the circuit breaker

• Absorbed by the circuit of relay

• Developed by the relay circuit

• None of the above

Buchholz relay can detect faults..........oil level in the transformer.

• Upper

• Below

• Same

• None of the above

Reactance relay is usually employed for the protection of

• Short lines only

• Medium lines only

• Long lines only

• Any line

Imbedance relay is usually employed for the protection of

• Short lines only

• Medium lines only

• Long lines only

• Any line

If the fault occurs near the impedance relay, the V/I ratio will be

• Constant for all distances

• Lower than that of if fault occurs away from the relay

• Higher than that of if fault occurs away from the relay

• None of the above

Merz-Price protection is employed for protection of

• Alternators

• Transformers

• Transmission lines

• Both A and B