Grounding/Ground Grids

Question 1

A low-resistance, well-designed, and well-constructed ground grid is necessary to provide improved ? .

Answer 1

worker safety

Question 2

One reason a well-grounded substation neutral provides improved power quality is because ? need a solid ground reference to properly operate switchgear.

Answer 2

control relays

Question 3

The substation ground grid protects workers and the public from ? and ? potentials.

Answer 3

touch / step

Question 4

If a person’s body is bridging across an open point in a ground grid during a system fault, the person can receive a fatal shock.

Answer 4

True

Question 5

The design of a substation ground grid starts with choosing a site location where ? is present, which has the ability to dissipate power surges.

Answer 5

good earth

Question 6

In a substation, the ground grid covers ? .

Answer 6

the entire area of the substation

Question 7

If multiple ground rods driven eight feet deep do not provide a low enough resistance to meet specifications, ? in order to achieve lower resistance.

Answer 7

a second rod can be joined to the first to go deeper

Question 8

If a ground grid needs lower resistivity, deep-drilled wells back-filled with ? can be used.

Answer 8

a highly conductive clay such as bentonite

Question 9

A substation ground grid is not subjected to a high electrical current.

Answer 9

False

Question 10

Electrical connections on a ground grid need to be fail-safe, so that when there is a rise in potential on the total grounding network in the station, everything will remain bonded together.

Answer 10

True

Question 11

The type of below-grade connector typically used on a substation grid is a(n) ? connection.

Answer 11

exothermic welded

Question 12

Training is required on how to properly install exothermic connectors.

Answer 12

True

Question 13

Crushed stone is a good product to cover a substation ground grid because it offers some protection when stepping from the grid to a ? .

Answer 13

remote ground

Question 14

Electrical connections are made at all crossover junctions of the grid.

Answer 14

True

Question 15

Electrical connections are made at all crossover junctions of the grid.

Answer 15

touch and step potentials

Question 16

Workers are protected from touch potentials in a substation because metal equipment such as transformers, switchgear, cable trays, and fences, are all connected to the ground grid.

Answer 16

true

Question 17

Workers are protected from ? because the design and spacing of the substation ground grid does not place one foot of a worker at a different potential from the other foot.

Answer 17

step potentials

Question 18

The public is protected from touch potentials because the fence is bonded to the ground grid, and the grid extends outside of the fence.

Answer 18

true