MCQs on Power Systems

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01․ Merze price current scheme protection is used in
transformer.
alternator.
both A and B.
bus bars.

Merze price current scheme protection is a differential protection used in transformer and alternators.
02․ The most suitable circuit breaker for short line fault without switching resistor is
oil circuit breaker.
air blast circuit breaker.
SF6 breaker.
none of these.

Under construction.
03․ Mho relay is used for the protection of
long transmission lines.
short length lines.
medium length lines.
no length criterion.

Under construction.
04․ IF the time of operation of a relay for unity TMS is 10 sec then the time of operation for 0.5 TMS is
5 sec.
10 sec.
20 sec.
none of these.

Under construction.
05․ Where the voltage is high and current to be interrupted is low, Which of following the breaker is preferable?
Oil CB.
Vacuum CB.
Air blast CB.
Any of these.

Under construction.
06․ A 60 Hz, 320 Km loss less line has sending end voltage 1.0 pu. The receiving end voltage on no-load is
1.1 pu.
1.116 pu.
1.088 pu.
none of these.

Under construction.
07․ Lightning arresters are used to protect electrical equipment against
direct strokes of lightning.
power frequency of over voltages.
over currents due to lightning stroke.
over voltages due to indirect lightning stroke.

Under construction.
08․ Resistance switching in normally employed in
bulk oil breakers.
minimum oil breakers.
all breakers.
air blast circuit breaker.

Under construction.
09․ The use of high speed circuit breakers
improves system stability.
decrease system stability.
reduces the short circuit current.
increased the short circuit current.

Under construction.
10․ Zero sequence currents can flow from a line into a transformer bank if the windings are in
delta / star.
ground star / delta.
star / grounded star.
delta / delta.

Under construction.
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