POWER PLANT

What do you call the protective angle between the Overhead ground wire and the power cable in the Transmission tower

• shielding angle

• surge angle

• clearing angle

• arcing angle

Disconnecting switch is provided for proper protection of electric substations and power plant. What is its main function.

• for protection of circuit breaker

• for maintenance purpose

• to break the system under fault

• for complete isolation

The highest magnitude of fault current will determine the size of _________, while the lowest magnitude will determine the size of_____________.

• fuse, relay

• circuit breaker, isolator

• circuit breaker, relay

• relay, circuit breaker

The PTs of a 220 kV transmission line have ratio of 132.76 kV: 66.375 V and are connected wye-wye. A voltmeter connected line to ground reads 66 V, what is the transmission line voltage?

• 223.15 kV

• 220.10 kV

• 228.63 kV

• 225.25 kV

The transfer bus scheme has the following characteristics EXCEPT one. Which one of this?

• It allows better continuity of service as compared with the single bus

• It allows the disconnection of circuit breakers for maintenance without Interrupting the service

• It is more flexible

• It is more costly than that of the single bus system

It is more costly than that of the single bus system

• Even with a circuit breaker failure, a station shutdown will not result.

• It gives more flexibility

• It reduces the likelihood of extended outages of any circuit due to circuit breaker trouble

• It permits breaker maintenance without feeder outage.

A large electric power distribution system is protected against surges and faults by

• high-speed relays detecting the trouble

• protective gaps crossing drain cells

• protective relays operating without a time delay

• radio communication system using flow frequency

Which of the following steps is used for isolating a circuit breaker for maintenance purposes?

• pull the substation fuses

• turn off the main generator

• open the disconnect switches

• ground the auxiliary contacts

In a generating and distribution system, current balance is provided by protective zones which are

• monitored by differential relays

• used to eliminate reflections on short transmission lines

• used to trip all circuit breakers in the system

• isolated during fault by disconnect switches

For protection of parallel feeders fed from one end the relays required are:

• Directional relay at both the ends.

• Non-directional relays at the source end and directional relays at the load end

• Directional relays at the source end and non-directional at the load end.

• Non-directional relays at both the ends