Key Terms Flashcards
Alternating Current
Alternating current means that the flow of electrical energy changes direction at a certain rate.
Amp
Short for ampere. An amp is defined as a quantity of electrons flowing past a given point in a given time.
Conductor Bundles
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.
Coulomb
A coulomb is a quantity measurement of electrons. There are 6,250,000,000,000,000,000 electrons in one coulomb.
Current
Current is defined as the rate of flow of electrons.
DELTA Systems
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.
Distribution
Lines that deliver power directly to the customer. Distribution lines most commonly operate between 2 kV and 34.5 kV.
Distribution Substation
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.
Hertz (Hz)
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.
Kilovolt
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.
Network Circuit Design
Circuits in metropolitan areas where the primary and secondary circuits are tied together in a grid.
Ohm
The ohm is the unit of measure for electrical resistance.
Ohm’s Law
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.
Phase
A term used referring to an energized conductor. A distribution main line feeder has three phases.
Primary
The high voltage portion of a distribution power line.
Resistance
Resistance is the opposition to current flow in an electrical circuit.
Radial Circuit Design
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.
Radial Tie Circuit Design
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.
RMS
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.
Secondary
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.
Service
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.
Sine Wave
A graphical representation of what is happening to voltage in an AC circuit over a period of time.
Sub Transmission
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.
Sub Transmission Substation
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.
Substations
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.
The Grid
A term used to describe the network of transmission lines that are interconnected across regions of the United States.
Transmission
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.
Transmission Substation
Substations that are used to tie transmission lines together, or to step voltage down from one transmission voltage to another.
Volt
The volt is a measure of electromotive force. Some find it easier to think of voltage as electrical pressure.
Watt
The watt is a unit of electrical power. One watt is produced when one amp flows through one volt of potential difference.
WYE Systems
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.
