Home > Customer Service > Glossary of Terms

Glossary of Terms

AIRBREAK: A manually operated switch used to interrupt or pick up load. It may be used by line workers for visual working clearance.

AIR CIRCUIT BREAKER (ACB): This piece of equipment isolates faulted lines and protects the substation. Air is used to extinguish the arc caused by the switch opening.

ALTERNATE CURRENT (AC): An electric flow that regularly reverses its direction. Each forward-backward motion interval is called a cycle. Electric current in the United States alternates with a frequency of 60 hertz or cycles per second.

ALTERNATIVE ENERGY SOURCES: Also known as supplemental energy sources such as methane, solar, wind, tidal, geothermal, fusion, and synfuels.

AMPERE (AMP): The unit for measuring the strength of electric current. It is proportional to the quantity of electrons flowing through a conductor past a given point in one second.

ARRESTER: A piece of equipment designed to protect the electrical system from lightning. Refer to as lightning arrester.

BASELOAD: Minimum amount of electric power delivered or required over a given period of time.

BILLING DEMAND: The demand upon which billing to a customer is based, as specified in the rate or by special contract. The demand does not necessarily coincide with the actual measured demand for the current month. It may be based on the highest demand in the past year or by a contract so it is necessary to refer to the customer's rate structure or contract.

BLOCK RATE: A rate structure that incorporates different kWh or kW prices for consumption at different levels. An example would be where we bill the customer the first 100 kWh at one price and all remaining kWh at a second price.

BREAKER: A device usually found in the home, on a pole or in a substation. It is designed to open automatically when a fault occurs. It can be operated manually or automatically.

BRITISH THERMAL UNIT (BTU): The standard unit for measuring quantity of heat energy. It is the amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit.

BROWNOUT: The reduction of voltage (and thus power) when demand for electricity exceeds generating capacity.

BACK TO TOP

BUS: Electrical conductors found in a substation that connects all the equipment to a common point.

BUSBAR: An electrical conductor in the form of rigid bars that serve as a common connection for two or more electric circuits.

BUSHING: An insulator found on electrical equipment where the wires attach to the equipment. Transformers and capacitors have bushings.

CAPACITY: Load capability of a generating unit, generating station, or other electrical apparatus.

CAPACITY COSTS: The fixed costs to generate electricity. These costs do not vary with consumption. Capacity costs are round-the-clock expenses incurred by the utility company whether or not generated units are in use.

CAPACITOR: Device used to correct poor power factor by causing a rise in voltage.

CIRCUIT: The completed path traveled by an electric current.

CIRCUIT BREAKER: An automatic switch that operates like a fuse and interrupts a circuit when too strong an electric current is passing through.

COGENERATION: A process utilizing industrial waste heat to generate electric power.

CONDUCTOR: A substance that easily allows the flow of electrons as electricity. Copper and aluminum wires are used, especially copper as it is a better conductor due to its internal molecular makeup.

CROSSARM: Wooden timber attached to the top of the pole to which the wires are attached.

DEMAND: The amount of load required by equipment actually taking service in any 15-minute demand interval, and is always less than or equal to the connected load of equipment at the location. Demand is measured in kilowatts (kW).

DEMAND CHARGES: Rate component charge that covers the cost of serving demand or load and that includes the cost of fixed generating, transmission and distribution capacity, i.e., for costs that do not vary with level of energy used.

DEMAND METER: A demand meter measures not only kWh but the highest kW of demand created in a given time period, normally the highest demand created in a 15-minute period.

DIRECT CURRENT (DC): Electricity that flows continuously in one direction.

DISCONNECT SWITCH: A switch used to isolate equipment.

BACK TO TOP

DISTRIBUTION: A system of delivering acceptable voltage electricity from transmission lines to individual customers.

ELECTRIC CIRCUIT: An electric circuit consisting of a power source, connecting wires or conductors, and a device that uses the electrical energy. The device that uses the energy is called the load. For current to flow in an electric circuit, there must be a complete path from the negative terminal of the power source, through the connecting wires and load, back to the positive terminal of the source. If a complete path does not exist, no current will flow, and the circuit is called an open circuit.

ELECTRICITY: Energy converted from natural resources or fuels and produced in a power plant. Electricity occurs in nature as lightning or static/friction.

ENERGY AUDIT: An analysis by trained personnel of the efficiency of heating, cooling, ventilating and other energy systems within a building.

ENERGY CHARGES: Rate component charge billed on the meter kWh usage, principally reflecting the cost of fuel and other variable costs. Non-demand metered rates contain kWh charges that also recover capacity related costs.

ENTRANCE CABLE: Wire that runs down the side of a house and attaches to the meter socket. This wire is owned by the customer and is their responsibility.

FUSE: A protection device found on the line. It is used to protect the system from faults. For example, if a fault occurs beyond the fuse point, the fuse will blow but the rest of the system will stay alive. When the fuse is blown, it sounds like a gun shot. Some older homes have fuses as well. Customers are encouraged to check their fuse box or breaker box before they call in with the power is out, to be sure the problem is on the utility system rather than within the home.

GENERATION: The process of producing electricity; also, the amount of electric energy, expressed in watt-hours.

GENERATOR: A device that takes fuel or other mechanical energy to produce electricity or electrical energy.

GIGAWATT (GW): One billion watts, useful for describing the capacity of large electrical energy systems.

GROUND: Used by line workers to ground electrical conductors to prevent accidental electrocution when working on lines.

GROUND ROD: A metal rod driven into the ground to which the ground wire is attached. Each house has a ground rod except in large cities, where the ground is usually attached to city water pipes.

HOT LINE WORK: A term used when line workers are working on the electric system with a live (hot) line.

BACK TO TOP

HYDROELECTRICITY: Producing electricity by using the force of falling water to turn the turbine blades, usually accomplished by damming a river to create a source of falling water.

INSULATOR: Any material that will not conduct electricity, such as rubber. Used on poles to carry wire and insulate the conductor from the ground.

INTERRUPTIBLE POWER: Power made available under special agreements that permit curtailment of power delivered by the company to the customer.

INTERRUPTIBLE RATE: Lower rate offered to customers, by special contract, who agree to periodic or intermittent cut-offs. Usually offered to industrial customers.

KILOWATT (kW): The rate at which electricity is used; a kilowatt is 1,000 watts. The basic unit of demand.

KILOWATT-HOUR (kWh): 1,000 watt-hours. The basic unit of electric energy equal to one kilowatt of power used for one hour. The amount of electricity sold or consumed is measured in kilowatt-hours.

LIGHTNING ARRESTOR: A device designed to absorb shock from lightning and prevent damage to substation equipment.

LOAD: The amount of electric power delivered or required at any specified point on the system. Load originates at the equipment of the customer. A light bulb is a load.

LOAD CONTROL: The load management technique of managing customer loads by directly controlling the operating time of a customer's major electric appliances, such as water heating, air conditioning and space heating .

LOAD FACTOR: Percentage of time a customer uses the full load potential, as measured by a demand meter. It is a determination of the amount of time the customer is at full load.

LOAD MANAGEMENT: Various ways of bringing the demand for electricity into balance with the supply, by the user or the utility or both controlling the time at which power is used.

MEGAWATT (MW): The generating capacity of utility generating equipment is expressed in megawatts. A megawatt is 1,000 kilowatts.

METER: A device that measures and records the amount of electricity used.

METER BOX OR METER SOCKET: The box found on the side of the house or mounted on a pole. The entrance cable comes into the top of the box and comes out the bottom to feed the residence. In some older residences, the meter box is inside the home.

NEUTRAL: Provides a return path for electricity and stabilizes the system.

PATROL: The practice of looking over a power line for trouble areas. This can be done on foot, in a vehicle or by helicopter.

BACK TO TOP

PEAK POWER: Electricity supplied during a period of the greatest demand.

PORTABLE TRANSFORMER: A transformer that can be moved quickly to replace a faulted transformer. It is usually a self-contained unit transported on a trailer.

POWER GRID: A network of electric power lines and associated equipment used to transmit and distribute electricity over a geographic area.

POWER TRANSFORMER: An electrical device that transforms voltage to lower levels.

PRIMARY VOLTAGE: The voltage of the circuit supplying power to a transformer is called the primary voltage, as opposed to the output voltage or load-supply voltage, which is called secondary voltage. In power supply practice the primary is almost always the high-voltage side and the secondary the low-voltage side of a transformer.

PUBLIC SERVICE BOARD : A governmental agency whose members are appointed by the governor to regulate electric utilities in Vermont. The board makes the final decisions regarding allowed revenue, rate structure, service territories, and the construction of major utility facilities.

PUBLIC SERVICE DEPARTMENT: An agency whose members represent the public's interest before the Public Service Board in regulatory proceedings.

PUBLIC UTILITIES REGULATORY POLICIES ACT (PURPA): A federal law setting out rate design standards for consideration by states. PURPA requires utilities to buy power at equitable rates from businesses that generate it as a by-product of some other industrial process (cogeneration).

RIGHT-OF-WAY: Private property acquired by a utility for generation, transmission and distribution facilities. Also, land obtained to run lines to houses. Signed agreements are obtained from land owners.

SCADA: This stands for "Supervisory Control And Data Acquisition". It is the remote control of breakers and generators from the Control Center. Loads are also monitored in this manner.

SERVICE CHARGE: The rate component charged to each customer in Vermont that is to recover costs associated with providing electric service to a customer that are not related to the amount of kWh provided. The charge covers metering, cost of billing, record keeping, meter reading and the service wire to the house.

SUBSTATION: A set of transformers that change the voltage of electrical energy to levels appropriate for end use.

SYSTEM LOSSES: The difference between the system net energy or power input and output resulting.

TARIFF: The schedule of all rates and services offered by CVPS filed with the state PSB.

BACK TO TOP

TEMPORARY SERVICE: Refers to electric service installed on a temporary basis to allow for construction of a new structure. Once a structure is completed, the temporary service is removed and permanent service installed.

THREE-PHASE: An A/C system with three currents, delivered on three separate wires with a forth wire as a neutral. Found on main lines and to service large customers.

TIME-OF-DAY-RATE: Also know as time-of-use (TOU) rate; charges customers according to when they use electricity. Customers pay more for electricity used during peak demand periods and pay less during the off-peak periods. These rates are structured to reflect the variation in the cost of service within the billing period.

TRANSFORMER: An electromagnetic device for changing the voltage of alternating current electricity.

TRANSMISSION LINE: Wires or cables through which high-voltage electric power is moved from point to point.

VOLTAGE (VOLT): The unit of electromotive force or electric pressure. It is the electromotive force which, if steadily applied to a circuit having a resistance of one ohm, will produce a current of one ampere.

VOLTAGE REGULATOR: A device used to regulate voltage. It is used to maintain constant voltage levels on the electric system.

WATT: The electrical unit of power or rate of doing work. The rate of energy transfer equivalent to one ampere flowing under a potential of one volt at unity power factor.

WATT-HOUR: The basic unit of electric energy equal to one watt of power supplied to or taken from an electric circuit steadily for one hour. The amount of electricity sold or consumed is measured in kilowatt-hours.

WEATHERHEAD: Used to protect the entrance cable from the elements, i.e. water running down the cable into the meter socket.

BACK TO TOP