Switchgear Protections

fuses ✘ relays ✘ fast switches ✘ circuit breakers ✔

voltage and current ✘ light intensity ✘ temperature ✘ all above ✔

Oil circuit breakers ✘ Air blast circuit breakers ✘ Minimum oil circuit breakers ✘ All of the above ✔

Impedance ✘ Reactance ✘ Either of the above ✘ None of the above ✔

Radiation ✘ Convection ✘ Conduction ✘ All of the above ✔

the spring tension ✘ the rate of flux built up ✘ armature core air gap ✘ all of the above ✔

burning ✘ arcing ✘ melting ✘ none of the above ✔

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 ✔

low currents circuits ✘ low voltages circuits ✘ high voltages and large currents circuits ✘ all circuits ✔

Air blast circuit breakers ✘ Circuit breaker with SF6 gas ✘ Vacuum circuit breakers ✘ Oil circuit breakers ✔