Protective Equipment

Question 1

The simplest way to protect an electrical substation from lightning is with ? protection.

Answer 1

direct strike

Question 2

According to the National Electrical Safety Code, substation shield (static) wire should be limited to a maximum design tension of ? per conductor.

Answer 2

2000 lbs

Question 3

If the transmission system entering a substation does not employ shielding, the substation shield wire should not extend beyond the substation fence.

Answer 3

False, extend 1 mile out of fence

Question 4

There should be ? connection(s) to the static wire at each support point in a substation.

Answer 4

2 separates

Question 5

Station class arresters are recommended for all substations of ? and above

Answer 5

10,000 kVA

Question 6

The only class arrester available for systems with voltages above ? are station class arresters.

Answer 6

150 kV

Question 7

Intermediate class arresters are available in ratings of 3 kilovolts through 69 kilovolts only.

Answer 7

False

Question 8

There are advantages of protecting the main transformer in smaller rural substations with ? . One advantage is the lower initial cost. Utilizing alternative methods requires auxiliary equipment like CTs and relays.

Answer 8

power Fuses

Question 9

One of the two reasons power fuses may be used on rural substations is that they require only minimal physical maintenance.

Answer 9

True

Question 10

Power fuses will protect the main substation transformer by operating in response to an upstream transmission line fault.

Answer 10

False

Question 11

One advantage of using power fuses to protect a substation transformer is that they can be opened or closed under full load.

Answer 11

False

Question 12

The term “circuit breaker” applies to breakers on ? of the main substation transformer.

Answer 12

both sides

Question 12

If substation power transformers are protected by fuses, the transformer surge arresters should be connected ? . This is to avoid stress and partial melting of the fuse link during an overvoltage event.

Answer 12

line side of the fuses

Question 13

A circuit breaker with external source and load connections made through conventional bushings is the ? type.

Answer 13

dead tank

Question 14

Circuit breakers utilizing one mechanical device to trip all three poles with linkage to gang the operation together are classified as ? breakers.

Answer 14

3-pole single-throw

Question 15

Air break switches that are part of a gas high side interrupter should operate de-energized and arc free.

Answer 15

True

Question 16

Circuit breakers using SF6 gas as the insulating medium are available with three operating mechanisms: pneumatic, hydraulic, and ? operated.

Answer 16

spring

Question 17

A circuit breaker’s rating is based on its ? capacity.

Answer 17

load current-carrying

Question 18

When installing or maintaining an oil circuit breaker, inspection and adjustment of the mechanism in both the open and closed position is performed. To open and close the breaker contacts, a ? is used.

Answer 18

manual jack

Question 19

The presence of hydrocarbon gases in oil is indicated by performing a ? test.

Answer 19

dissolved gas analysis

Question 20

When inspecting a substation circuit breaker, a broken seal or cracked bushing may mean there is water in the oil.

Answer 20

true

Question 21

PCBs may be present in a substation oil-filled piece of equipment if it was built before ? .

Answer 21

1980

Question 22

SF6 gas is ? times heavier than air and will settle in low places.

Answer 22

5 times

Question 23

When working on or near a gas breaker, a rotten egg odor is an indication of ? .

Answer 23

SF6 gas that has been exposed to moisture

Question 24

At a 3-phase circuit breaker installation, the control cabinet is located in the ? .

Answer 24

middle

Question 25

Substation breakers can be operated by AC or DC controls.

Answer 25

true