Grounding/Ground Grids Flashcards
A low-resistance, well-designed, and well-constructed ground grid is necessary to provide improved ? .
worker safety
One reason a well-grounded substation neutral provides improved power quality is because ? need a solid ground reference to properly operate switchgear.
control relays
The substation ground grid protects workers and the public from ? and ? potentials.
touch / step
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.
True
The design of a substation ground grid starts with choosing a site location where ? is present, which has the ability to dissipate power surges.
good earth
In a substation, the ground grid covers ? .
the entire area of the substation
If multiple ground rods driven eight feet deep do not provide a low enough resistance to meet specifications, ? in order to achieve lower resistance.
a second rod can be joined to the first to go deeper
If a ground grid needs lower resistivity, deep-drilled wells back-filled with ? can be used.
a highly conductive clay such as bentonite
A substation ground grid is not subjected to a high electrical current.
False
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.
True
The type of below-grade connector typically used on a substation grid is a(n) ? connection.
exothermic welded
Training is required on how to properly install exothermic connectors.
True
Crushed stone is a good product to cover a substation ground grid because it offers some protection when stepping from the grid to a ? .
remote ground
Electrical connections are made at all crossover junctions of the grid.
True
Electrical connections are made at all crossover junctions of the grid.
touch and step potentials