power system protection

which of these are symmetrical fault

• L-G

• L-L-G

• L-L

• L-L-L

The component which provides a signal to circuit breaker under the fault condition:

• Isolator

• Fuse

• Relay

• CT

The correct statement about Buchholz relay

• It can only be used with largely sized alternators

• It is installed with largely sized transformers which have no conservator tank

• It can detect incipient faults

• It should never be used with oil immersed transformers

Buchholz relay is used to protect:

• ALTERNATOR

• INDUCTION MOTOR

• SYNCHRONOUS MOTOR

• TRANSFORMER

____________________ is/are an instantaneous relay/s:

• PMMC type

• Shaded pole type

• Both of these

• None of these

Plug setting multiplier is defined as the ratio of:

• Fault current in relay coil x Pick up current

• Fault current in relay coil / Pick up current

• Fault current in relay coil x Transformer secondary turns

• Fault current in relay coil / Transformer secondary turns

High-speed circuit breakers result in:

• Increased stability of power systems

• decreased stability of power systems

The basic purpose of a relay is to:

• Detect the fault

• Remove the fault

• Trip the circuit

• All of these

In Electrical power protection schemes ______________ transformer is used:

• VT

• CAPACITIVE VOLTAGE TRANFORMER

• Both of these

• None of these

The equipment which has lowest chances of fault occurrence:

• Alternator

• Transformer

• Switchgear

• Induction motors