Switchgear protections

[amp_mcq option1=”Have low contact resistance” option2=”Be clean and smooth” option3=”Be of sufficient size and proper shape” option4=”Have all above properties” correct=”option4″]

Detailed SolutionIn order that current should flow without causing excessive heating or voltage drop, the relay contacts should

[amp_mcq option1=”zero current” option2=”maximum current” option3=”minimum voltage” option4=”maximum voltage” correct=”option1″]

Detailed SolutionArc in a circuit breaker is interrupted at

[amp_mcq option1=”1.5 sec” option2=”5 to 10 sec” option3=”5 to 20 sec” option4=”20 to 30 sec E. none of the above” correct=”option1″]

Detailed SolutionThe relay with inverse time characteristic will operate within

[amp_mcq option1=”Air blast circuit breakers” option2=”Circuit breaker with SF6 gas” option3=”Vacuum circuit breakers” option4=”Oil circuit breakers” correct=”option3″]

Detailed SolutionWhich of the following circuit breakers has high reliability and minimum maintenance ?

[amp_mcq option1=”transposing transmission as well as communication lines” option2=”increasing the height of the trans-mission line tower” option3=”increasing the distance between the two lines” option4=”all of the above” correct=”option4″]

Detailed SolutionThe interaction between a transmission line and communication line is minimized by

[amp_mcq option1=”low currents circuits” option2=”low voltages circuits” option3=”high voltages and large currents circuits” option4=”all circuits” correct=”option3″]

Detailed SolutionOil switches are employed for

[amp_mcq option1=”Lightning arresters” option2=”Relays” option3=”Step-down transformer” option4=”Switchgear” correct=”option1″]

Detailed SolutionWhich of the following devices will receive voltage surge first travelling on the transmission line ?

[amp_mcq option1=”11 kV” option2=”33 kV” option3=”60 kV” option4=”110 kV” correct=”option4″]

Detailed SolutionFor cost and safety, the outdoor substations are installed for voltages above

[amp_mcq option1=”good selectivity and reliability” option2=”economy and simplicity” option3=”high speed and selectivity” option4=”all of the above” correct=”option4″]

Detailed SolutionAn efficient and a well designed protective relaying should have

[amp_mcq option1=”Photoelectric effect” option2=”Electrostatic effect” option3=”Heating effect” option4=”Magnetic effect” correct=”option3″]

Detailed SolutionOn which of the following effects of electric current a fuse operates?