Unit 3-4 Lesson 14

A cap and pin insulator can be damaged in handling by picking up a string of insulators and ? . a. allowing it to bend b. carrying it upside down c. keeping it horizontal and rigid d. letting it hang straight down

A

Hollow post insulators are used in a substation as ? . a. bushings for equipment b. control cable raceways c. moisture-repellent channels d. steel cable routing conduits

A

If lightning causes an insulator flashover, the electrical insulation rating that has been exceeded is the insulator's ? . a. BIL b. dielectric constant c. pin rating d. skirt size

A

Insulators used on overhead circuits are typically made of polymeric, porcelain, or ? . a. glass b. polyethylene c. PVC d. wood

A

An insulator will fail when ? . a. a lightning strike lasts longer than 2 cycles b. electric current punctures through the insulation to ground c. the insulator BIL is too high for the voltage it is used on d. the insulator is too long for the bus work

B

If insulators are typically rated at 11 kilovolts each, a 13.2-kilovolt line would require ? insulator(s). a. 1 b. 2 c. 3 d. 4

B

The ? on an insulator increases the leakage distance that electrical current would need to travel to flash to ground. a. cross arm pin used b. petticoat or skirt c. pre form d. type of bolts used

B

The mechanical strength of a polymeric insulator comes from the internal ? . a. baked clay plug b. central fiber reinforced plastic rod c. lead rod d. twin steel bands

B

The two functions of the glaze on a porcelain insulator are to help shed dirt and ? . a. absorb galloping vibrations b. bead water c. deflect lightning d. melt ice

B

The advantage polymeric hollow post insulators have over porcelain hollow post insulators is that ? . a. the inside surfaces are porous b. they can withstand higher temperatures c. they do not shatter and produce sharp shrapnel d. they have a higher amperage rating

C

The semi-conducting glaze used on insulators minimizes corona, radio, and television interference because the uniform conducting surface ? . a. allows a layer of ionized particles to form b. deflects overvoltages c. reduces voltage stress at any one point d. spreads out the current

C

A string of fourteen 50 kip, cap, and pin insulators has a rated strength of ? . a. 14,000 lbs b. 24,000 lbs c. 40,000 lbs d. 50,000 lbs

D

If pin cap insulators are used in a substation, they are used on the ? . a. control house circuits b. high-voltage side c. lightning arrester wire d. low-voltage side

D

Solid post insulators are used in a substation to support bus and ? . a. ground gradient mats b. isolation fences c. power transformers d. switch gear

D

An insulator with a BIL of 550 kilovolts is the appropriate insulator for a 500-kilovolt circuit. Select one: True False

False

Polymeric posts do not have a mechanical strength rating. Select one: True False

False

Cap and pin insulators are designed for tension installations. Select one: True False

True

Rough handling of insulators can cause a major power outage at some point in the future. Select one: True False

True

The insulator glaze that intentionally allows a leakage current to generate heat and help keep the surface dry is made from a semi-conducting glaze. Select one: True False

True

Tracking paths on the surface of insulators are conductive. Select one: True False

True