Recent questions tagged fault

Description : Give the causes and impact and reasons of grid system fault. 

Last Answer : Following are the causes/reasons grid system fault: 1. Major imbalance between generation and consumption i.e. demand is more than generation. 2. Low frequency, due to some faults the frequency ... of supply and causes inconvenience to people. 6. Disturb the routine work of common all people.

Description : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be

Last Answer : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be 10

Description : If the % reactance upto the fault point is 20%, then the short circuit current will be

Last Answer : If the % reactance upto the fault point is 20%, then the short circuit current will be 5 times the full load current

Description : If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then  (A) zero sequence currents are present on both sides of the transformer  (B) ... side  (D) zero sequence currents are present on the primary side but not on the secondary side

Last Answer : If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then zero sequence currents are absent on both sides of the transformer 

Description : If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be

Last Answer : If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug setting multiplier will be 10 A

Description : A shunt fault is characterized by (A) Increase in current, frequency and pf (B) Increase in current, reduction in frequency and pf (C) Increase in current and frequency, reduction in pf (D) Decrease in current and frequency

Last Answer : B

Description : With fault clearing time, the transient stability of a power system

Last Answer : With fault clearing time, the transient stability of a power system decreases

Description : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Last Answer : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection

Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.

Last Answer : Reactance relay is preferred for phase fault on short transmission line.

Last Answer : Fault diverters are basically fast switches.

Description : In which fault the maximum short circuit current occurs?

Last Answer : In three phase bolted fault the maximum short circuit occurs.

Description : Which is the most common type of fault?

Last Answer : Single phase to ground fault is the most common type of fault.