Power Systems
Which one of the following relays has the capability of anticipating the possible major fault in a transformer?

 Differential relay
 Over fluxing relay
 Over current relay
 Buchholz relay

ANSWER DOWNLOAD EXAMIANS APP

Power Systems
In a biased differential relay the bias is defined as the ratio of

  number of turns of restraining and operating coil.
  fault current and operating coil current.
  fault current and restraining coil current.
  operating coil current and restraining coil current.

ANSWER DOWNLOAD EXAMIANS APP

Power Systems
Gross head of an hydroelectric power station is

 all of above.
 the height of water level in the river where the storage is provided.
  the difference of water level between the level in storage and tail race.
 the height of water level in the river where the tail race is provided.

ANSWER DOWNLOAD EXAMIANS APP

Power Systems
A lossless power system has to serve a load of 250 MW. There are two generators(G1 and G2) in the system with cost curves C1 and C2 respectively defined as follows: C1 = PG1+0.055P²G1 C2 = 3 PG2 + 0.03 P²G2 Where PG1 and PG2 are the MW injections from generators G1 and G2 respectively. Thus, the minimum cost dispatch will be

 PG1 = 100 MW and PG2 = 150 MW
 PG1 = 150 MW and PG2 = 100 MW
 PG1 = 0 MW and PG2 = 250 MW
 PG1 = 250 MW and PG2 = 0 MW

ANSWER DOWNLOAD EXAMIANS APP

Power Systems
Which of the following statements is/are true? The elements of each row of a Y bus matrix for load flow studies in power system add up to zero

 if both 2 and 3 are satisfied
 always
 if the shunt admittances at the buses are ignored
 if the mutual couplings between transmission lines are absent

ANSWER DOWNLOAD EXAMIANS APP