Power glossary meaning of power terms

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Power glossary meaning of power terms

GLOSSARY ON POWER

GLOSSARY

Active Power :- See real power

Alternating current:- an electrical current which reverses direction repeatedly due to a change in voltage which occurs at the same frequency. Often abbreviated AC or ac.

Alternator:- an electric generator designed to produce alternating current. Usually consists of rotating parts which created the changing magnetic field to produce the alternating current.

Ammeter:- An electric meter used to measure current, calibrated in amperes

Amperes:- The basic SI unit measuring the quantity of electricity. The unit for the electric current; the flow of electrons. One amp is 1 coulomb passing in one second. One amp is produced by an electric force of 1 volt acting across a resistance of 1 ohm.

Ancillary Services:- Operations provided by hydroelectric plants to ensure stable and reliable electricity delivery and optimize transmission efficiency.

Apparent Power: - the mathematical product of voltage and current on ac systems. Since voltage and current may not be in phase on ac systems, the apparent power thus calculated may not equal the real power, but may actually exceed it. Reactive loads (inductance and/or capacitance) on ac systems will cause the apparent power to be larger than the real power.

Armature:- That part of an electric generator in which the voltage is induced.

Base load:- The minimum amount of electric power delivered or required over a given period of time at a steady rate.

Battery:- a group of two or more cells connected together to provide electrical current. Sometimes also used to describe a single cell which converts chemical energy to electrical current.

Black out:- a complete loss of power lasting for more than one cycle. A black-out can damage electronics, corrupt or destroy data, or cause a system shutdown. Also known as power outage.

Breakdown voltage:- The voltage at which an insulator or dielectric ruptures, or at which ionization and conduction take place in a gas or vapor.

Brown out:- a prolonged sag, occurring when incoming power is reduced for an extended period. Usually caused when demand is at its peak and the line becomes overloaded

Cable:- A conductor with insulation, or a stranded conductor with or without insulation and other coverings (single-conductor cable), or a combination of conductors insulated from one another (multiple-conductor cable).

Capacitor:- a device that stores electrical charge usually by means conducting plates or foil separated by a thin insulating layer of dielectric material. The effectiveness of the device, or its capacitance, is measured in Farads.

Cavitations:- Noise or vibration causing damage to the turbine blades as a result of bubbles that form in the water as it goes through the turbine. This causes a loss in capacity, head loss, efficiency loss.

Cogeneration:- The process in which fuel is used to produce heat for a boiler-steam turbine or gas for a turbine. The turbine drives a generator that produces electricity, with the excess heat used for process steam.

Combined Cycle:- An electric generating technology in which electricity is produced from otherwise lost waste heat exiting from one or more gas (combustion) turbines. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for utilization by a steam turbine in the production of electricity. This process increases the efficiency of the electric generating unit.

Compact Fluorescent Light:- Lights that use a lot less energy than regular light bulbs. We can use compact fluorescent lights for reading lights and ceiling lights.

Conductor:- A wire or combination of wires not insulated from one another, suitable for carrying electric current.

Conduits:- Conduits are hollow tubes running from manhole to manhole in an underground transmission or distribution system.

Connection:- That part of a circuit that has negligible impedance and that joins components, devices, etc., together.

Current:- the flow of electricity commonly measured in amperes

Dam:- A wall built across a river to stop the water and make a lake.

Demand factor:- For an electrical system or feeder circuit, this is a ratio of the amount of connected load (in kva or amperes) that will be operating at the same time to the total amount of connected load on the circuit.
Demand Side Management:- The planning, implementation, and monitoring of utility activities designed to encourage consumers to modify patterns of electricity usage, including the timing and level of electricity demand. It refers only to energy and load-shape modifying activities that are undertaken in response to utility-administered programs. It does not refer to energy and load-shape changes arising from the normal operation of the marketplace or from government-mandated energy efficiency standards. Demand-Side Management (DSM) covers the complete range of load-shape objectives, including strategic conservation and load management, as well as strategic load growth.

Deregulation:- The establishment of a competitive marketplace for electricity that allows customers to buy power from whomever they wish

Dielectric:- Any insulating medium that intervenes between two conductors. (2) A material that, having the property required to establish an electric field, is recoverable in whole or in part as electric energy.

Direct Current:- electrical current that normally flows in one direction only. Abbreviated dc.

Distribution System:- The portion of an electric system that is dedicated to delivering electric energy to an end user

Earth:- The conductive mass of the Earth, whose electric potential at any point is conventionally taken as zero.

Electric Circuit:- Path followed by electrons from a power source (generator or battery) through an external line (including devices that use the electricity) and returning through another line to the source.

Electric Current:- A flow of electrons; electricity

Electricity:- A form of energy produced by the movement of electrons.

Energy Efficiency:- Refers to programs that are aimed at reducing the energy used by specific end-use devices and systems, typically without affecting the services provided.

Filter:- a device made up of circuit elements designed to pass desirable frequencies and block all others. It typically consists of capacitors and inductors

Flow:- Volume of water, expressed as cubic feet or cubic meters

Frequency:- the number of complete alternations or cycles per second of an alternating current. It is measured in Hertz. The standard frequency in Ghana is 50 Hz. However, in some other countries the standard is 60 Hz

Generation:- The process of producing electric energy by transforming other forms of energy; also, the amount of electric energy produced, expressed in watt-hours (Wh).

Generator:- a rotating machine which converts mechanical energy into electrical energy.

Greenhouse Effects:- The increasing mean global surface temperature of the earth caused by gases in the atmosphere (including carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbon). The greenhouse effect allows solar radiation to penetrate but absorbs the infrared radiation returning to space.

Grid:- The layout of an electrical distribution system.

Ground:- A large conducting body (such as the earth) used as a common return for an electric circuit and as an arbitrary zero of potential.

Harmonic Distortion:- a measure of the degree to which the impedance of a protection equipment affects the shape of the output voltage waveform. Distortion is stated as a percentage and may refer to any single harmonic or to the total waveform, in which case it is referred to as "total harmonic distortion" (THD).

Head:- Vertical change in elevation, expressed in either feet or meters, between the head water level and the tailwater.

Impedance:- the total effects of a circuit that oppose the flow of an ac current consisting of inductance, capacitance, and resistance. It can be quantified in the units of ohms.

Insulator:- A material through which electric charges cannot move. Some examples of good insulators are: rubber, wool, and glass, plastic, and dry air.

Kilo watt-hour:- unit of energy or work equal to one kilowatt for one hour. Abbreviated as kwh or KWH. This is the normal quantity used for metering and billing electricity customers.

Lightning:- a natural spark produced between charged layers of cloud or between a cloud and the ground.

Load:- a device which consumes electrical power and is connected to a source of electricity.

Load factor:- is the average power divided by the peak power over a period of time.

Load-shedding:- partial or total disruption of supply to customers caused by the supplier as the supplier may deem necessary to ensure safety of personnel, equipment and system integrity.

Megger:- A test instrument fpr measuring the insulation resistance of conductors and other electrical equipment; specifically, a megaohm (million ohms) meter

Motor:- A machine that converts electrical energy to mechanical energy

Ohm:- The unit of measurement of electrical resistance. The resistance of a circuit in which a potential difference of 1 volt produces a current of 1 ampere.

Overload:- Load greater than the load for which the system or mechanism was intended.

Outage:- The period during which a generating unit, transmission line, or other facility is out of service

Parallel connection:- A way of joining two or more electricity-producing devices (i.e., Photovoltaic cells or modules) by connecting positive leads together and negative leads together; such a configuration increases the current.

Peak load/demand:- The maximum load during a specified period of time.

Power:- The rate at which energy is transferred. Electrical energy is usually measured in watts. Also used for a measurement of capacity.

Power factor:- the ratio of real power to apparent power delivered in an ac electrical system or load. Its value is always in the range of 0.0 to 1.0 or 0% to 100%. A unity power factor (1.0) indicates that the current is in phase with the voltage and that reactive power is zero.

Power Pool:- An association of two or more interconnected electric systems having an agreement to coordinate operations and planning for improved reliability and efficiencies

Rated voltage:- The maximum voltage at which an electric component can operate for extended periods without undue degradation or safety hazard.

Reactive Power:- the mathematical product of voltage and current consumed by reactive loads. Examples of reactive loads include capacitors and inductors. These types of loads when connected to an AC voltage source will draw current, but since the current is 90o out of phase with the applied voltage, they actually consume no real power in the ideal sense.

Real Power:- the rate at which work is performed or energy is transferred. Electric power is commonly measured in watts or kilowatts. The term real power is often used in place of the term power alone to differentiate from reactive power. Also called active power.

Rectifiers:- A rectifier is a device used to convert alternating current to direct current(rectification).

Regulation:- The government function of controlling or directing economic entities through the process of rulemaking and adjudication.

Relays:- A relay is a low-powered device used to activate a high-powered device. Relays are used to trigger circuit breakers and other switches in substations and transmission and distribution systems.

RMS:- Root Mean Square

Rotor:- The movable plates of a variable capacitor.

Sag:- a momentary decrease from nominal voltage lasting one or more line cycles. Also known as a temporary undervoltage (TUV).

Series connection:- A way of joining circuits by connecting positive leads to negative leads; such a configuration increases the voltage.

Service drop:- Run of cables from the power company's aerial power lines to the point of connection to a customer's premises

Short Circuit:- a low resistance connection unintentionally made between points of an electrical circuit which may result in current flow far above normal levels.

Small Hydro:- Hydro power plants that produce 30 MW or less.

Standby Facility:- A facility that supports a utility system and is generally running under no load. It is available to replace or supplement a facility normally in service.

Stator:- The stationary coils of a generator.

Substations:- A high-voltage electric system facility. It is used to switch generators, equipment, and circuits or lines in and out of a system. It also is used to change AC voltages from one level to another, and/or change alternating current to direct current or direct current to alternating current

Surge:- A surge is a prolonged over-voltage condition. Such can damage electronics and corrupt or destroy data.

SVC:- Static Voltage Control

Switch:- A device that opens or closes a circuit. This prevents or allows a current to flow

Tariff:- A set of rates and regulations put out by a utility that determines how much bundled customers pay for electricity.

Three Phase:- an ac electric system or load consisting of three conductors energized by alternating voltages that are out of phase by one third of a cycle. This type of system has advantages over single-phase including the ability to deliver greater power using the same ampacity conductors and the fact that it provides a constant power throughout each cycle rather than a pulsating power, as in single-phase. Large power installations are three-phase.

Transformer:- a device that converts one ac voltage and current to a different voltage and current. Constructed using two or more coils of wire around a common magnetic core. The energy is transferred from one coil, usually considered the primary winding, to the other coil, the secondary winding by means of mutual induction in the magnetic core. Transformers are an efficient and economical means of transferring large amounts of ac electric power at high voltages. This is the primary advantage of ac systems over dc systems.

Transmission:- The movement or transfer of electric energy over an interconnected group of lines and associated equipment between points of supply and points at which it is transformed for delivery to consumers, or is delivered to other electric systems. Transmission is considered to end when the energy is transformed for distribution to the consumer

Turbine:- A machine for generating rotary mechanical power from the energy of a stream of fluid (such as water, steam, or hot gas). Turbines convert the kinetic energy of fluids to mechanical energy through the principles of impulse and reaction, or a mixture of the two

Turns ratio:- ratio of number of windings on the primary side to number of winding on secondary side of an electrical machine e.g. transformer.

Utility:- The public company responsible for ensuring energy delivery and maintaining electrical equipment for a given area.

Uninterruptible Power Supply:- a device that provides a constant regulated voltage output in spite of interruptions of the normal power supply. It includes filtering circuits and is usually used to feed computers or related equipment which would otherwise shutdown on brief power interruptions. Abbreviated UPS.

Volt:- A unit of measure of the force, or 'push,' given the electrons in an electric circuit. One volt produces one ampere of current when acting on a resistance of one ohm.

Waveform:- The shape of the curve graphically representing the change in the ac signal voltage and current amplitude, with respect to time.

Source : http://www.energycom.gov.gh/old/downloads/Glossary_Dictionary/GLOSSARY%20ON%20POWER.doc

Web site link to visit: http://www.energycom.gov.gh/

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