Formative Power System Protection

The main objective of power system protection

• minimize repair cost

• ensure safety personnel

• protect transformer

• isolate a faulty section from healthy power system

Basic requirement of evaluating power system protection are.... EXCEPT

• to detect smallest abnormalities

• ability to select either to operate or not

• minimum cost while perform required task

• ability to isolate fault in 1 minute

The figure show line-to-line fault, also known as UNSYMMETRICAL FAULT

• True

• False

Basic components of protection consists of..

• Relay, Fuse, CT

• Busbar, coil, circuit breaker

• CT, Relay, Circuit breaker and DC battery

• Fuse, circuit breaker

Switchgear are used in power system for... EXCEPT

• Switching

• Controlling

• Resisting

• Protecting

Choose the correct combination for switchgear equipment

• Decision making: Protective relay, lightning arrester, fuse

• Switching: Relay, lightning arrester, isolator

• Controlling: Relay, lightning arrester, fuse

• Switching: Circuit breaker, isolator, fuse

For rated current 500A, which circuit breaker are advised to be use

• MCB

• MCCB

• ACB

• Oil Circuit Breaker

Suggest a fuse rating for 240V, 2kW appliances

• 3A

• 5A

• 10A

• 13A

Oil circuit breaker use __________oil as insulator in arc extinction

• cooking

• diesel

• transformer

• conductor

SF6 gas is use as arc quenching medium due to ______

• low dielectric material

• electronegative gas and able to absorb free electron

• inert gas and able to release free electron

• good smell