Key Terms

Question 1

Alternating Current

Answer 1

Alternating current means that the flow of electrical energy changes direction at a certain rate.

Question 2

Amp

Answer 2

Short for ampere. An amp is defined as a quantity of electrons flowing past a given point in a given time.

Question 3

Conductor Bundles

Answer 3

A term used to indicate more than one conductor per phase. Conductor bundles are found on transmission lines and can be two, three or four bundle.

Question 4

Coulomb

Answer 4

A coulomb is a quantity measurement of electrons. There are 6,250,000,000,000,000,000 electrons in one coulomb.

Question 5

Current

Answer 5

Current is defined as the rate of flow of electrons.

Question 6

DELTA Systems

Answer 6

A DELTA distribution powerline has only three phases. The term DELTA refers to how the substation transformers, which are the source of the distribution line, are wired.

Question 7

Distribution

Answer 7

Lines that deliver power directly to the customer. Distribution lines most commonly operate between 2 kV and 34.5 kV.

Question 8

Distribution Substation

Answer 8

Substations that are used to step voltage down from sub transmission levels to distribution levels. Distribution circuits leave these stations and deliver power directly to the customers.

Question 9

Hertz (Hz)

Answer 9

Hertz is the unit of measure for frequency, just as volts is the unit of measure for electrical pressure. Electrical systems in the United States and Canada operate at 60 Hz, or 60 cycles per second.

Question 10

Kilovolt

Answer 10

Kilo is metric for 1000. A kilovolt would be equal to 1000 volts and would be denoted as 1 kV. A 500 kV line would be operating at 500.000 volts.

Question 11

Network Circuit Design

Answer 11

Circuits in metropolitan areas where the primary and secondary circuits are tied together in a grid.

Question 12

Ohm

Answer 12

The ohm is the unit of measure for electrical resistance.

Question 13

Ohm’s Law

Answer 13

Ohm’s Law describes the mathematical relationship between voltage, amperage, and resistance. In its simplest form, it states that it takes one volt to push one amp through one ohm of resistance.

Question 14

Phase

Answer 14

A term used referring to an energized conductor. A distribution main line feeder has three phases.

Question 15

Primary

Answer 15

The high voltage portion of a distribution power line.

Question 16

Resistance

Answer 16

Resistance is the opposition to current flow in an electrical circuit.

Question 17

Radial Circuit Design

Answer 17

Independent distribution circuits that “radiate” from the substation into the service area. There is no other source should a section of the line need to be cleared.

Question 18

Radial Tie Circuit Design

Answer 18

Circuits that are tied to circuits from the same substation or another substation. Power can be supplied from other circuits should a section of line need to be cleared.

Question 19

RMS

Answer 19

RMS is an acronym for root means square and is a value of AC voltage that will produce the same amount of power as a like value of DC voltage.

Question 20

Secondary

Answer 20

The low voltage portion of a distribution power line that runs from pole to pole on overhead systems or padmount to pedestal in underground systems.

Question 21

Service

Answer 21

The low-voltage portion of a distribution power line that runs from pole to customer on overhead systems or from pedestal to customer on underground systems.

Question 22

Sine Wave

Answer 22

A graphical representation of what is happening to voltage in an AC circuit over a period of time.

Question 23

Sub Transmission

Answer 23

Lines that move medium quantities of power to distribution substations at the load centers. Sub transmission circuits are most commonly energized at 44 kV, 69 kV, 115 kV, and 138 kV.

Question 24

Sub Transmission Substation

Answer 24

Substations that are used to step voltage down from transmission levels to sub transmission levels. Sub transmission circuits leave these stations and travel to distribution substations.

Question 25

Substations

Answer 25

Substations change voltage of circuits, connect or disconnect lines or equipment from each other, and control the flow of power by adjusting voltage and current.

Question 26

The Grid

Answer 26

A term used to describe the network of transmission lines that are interconnected across regions of the United States.

Question 27

Transmission

Answer 27

Lines that move large quantities of power over long distances at high voltages and are most commonly energized at 765 kV, 500 kV. 345 kV, or 230 kV.

Question 28

Transmission Substation

Answer 28

Substations that are used to tie transmission lines together, or to step voltage down from one transmission voltage to another.

Question 29

Volt

Answer 29

The volt is a measure of electromotive force. Some find it easier to think of voltage as electrical pressure.

Question 30

Watt

Answer 30

The watt is a unit of electrical power. One watt is produced when one amp flows through one volt of potential difference.

Question 31

WYE Systems

Answer 31

A WYE distribution powerline has three phases and a neutral or three phases. The term WYE refers to how the substation transformers, which are the source of the distribution line, are wired.