Glossary of Electric Station Operator Terms
1. ACCIDENT PREVENTION TAGS (APTs): Temporary signs or tags that have preprinted instructions and markings used
to:
*Restrict operation or other action so that personnel and or systems and components are protected
*Warn that the tagged system or component is in a condition for test or maintenance activities
*Indicate that the system or component is under the operating jurisdiction of an organizational unit other than the operating agent.
2. AIR CIRCUIT BREAKER: A circuit breaker in which the interruption occurs in air.
3. ALTERNATING CURRENT: That form of electric current that changes in magnitude and polarity in what
is normally a regular pattern for a given time period.
4. AMMETER: An instrument for measuring electric current.
5. AMPERE: The unit of current flow of electricity. One ampere is equal to one coulomb per second flow.
6. APPARENT POWER: For single phase, the current in amperes times the electromotive force in volts equals
the apparent power in volt-amperes. This term is used for alternating current circuits because the current flow is not always in phase with
the electromotive force; hence, amperes times volts does not necessarily give the true power. Apparent power for three-phase circuits
equals volts times amperes times 1.73.
7. AUTHORIZED PERSON: A person that is authorized to receive Work Authorities on circuits and equip-
ment from the Load Dispatcher or their Field Representatives. Certification as an Authorized Person is required in order to hold any form of
Work Authority.
8. AUTOMATIC RECLOSER (ARs): An AR (Auto Recloser) is a reclosing device (relay), or a function of an
IED, that initiates the reclosing of a circuit after it has been opened by a protective relay.
,9. AUTOTRANSFORMER: A transformer in which the primary and secondary have a common winding.
10. AUTOMATIC RECLOSING: A circuit breaker feature that will cause the CB to reclose automatically after
it has relayed.
11. AUTOMATIC TRANSFER SWITCH (ATS): An ATS is a device used to automatically transfer con-nections from
one circuit to another, commonly used for transferring a station service load from a preferred source to an alternate source.
12. BANK: One or more transformers that furnish three-phase power to a load.
13. BANK OF TRANSFORMERS: Any group of transformers connected together with some point on each
winding held in common. It may be for the purpose of voltage transformation or circuit isolation.
14. BARRICADE: A physical obstruction placed to warn against accidental contact with a hazard or restrict entry into a
hazard area. Barricades may be plastic Barricade tape of any color, flags, or any other device that will serve this purpose.
15. BATTERY: A group of several cells connected together as a unit for furnishing electric current.
16. BELT CIRCUITS: Overhead or underground circuits connecting receiving and switching stations together
and through which power can flow in either direction.
17. BID: A request to program complex or supplemental work...usually in advance...on Power System equipment, that
requires a Clearance or OK TO.
18. BLADE: The hinged or moving part of a disconnect through which current flows.
19. BLOCK DIAGRAM: A symbolic diagram; a diagram depicting the distributing stations supplied by a
receiving station as rectangles and all lines or cables connecting them as solid or dashed lines respectively; and usually referred to as a
34.5kV System block diagram.
20. BREAKER: See CIRCUIT BREAKER.
21. BUS: A bus conductor, or group of conductors, which serves as a common connection for several circuits within
, a station or switchyard.
22. BUS TIE: The means by which two separate buses (Bus No. 1 and Bus No. 2) may be electrically connected together
through a set of disconnects and circuit breaker.
23. CABLE: 1. An electrical circuit that is entirely underground is designated as a Cable. 2. The underground portion of a
combination electrical circuit. 3. The type of conductor that is installed underground.
24. CAPACITANCE: The ability of a conductor to store an electric charge.
25. CAPACITIVE REACTANCE: The opposition offered by capacitance to the flow of current and which is
expressed in ohms.
26. CAPACITOR: A device that stores an electric charge; two electrodes or group of electrodes called plates and which are
separated by an insulator or dielectric.
27. CAPACITY: The number of amperes of electric current a conductor, switch, circuit breaker, disconnect, bank, etc., will
carry without becoming overly heated.
28. CB, AIR: A breaker in which the interruption takes place in air.
29. CB, AIR BLAST: A breaker in which the interruption of current is accomplished with a blast of compressed
air supplied from an air compressor system.
30. CB, GAS: A breaker in which the interruption takes place in a pressurized gas chamber, normally SF6.
31. CB, OIL: A breaker in which the interruption takes place in oil.
32. CB, VACUUM: A breaker in which the interruption takes place in a vacuum.
33. CELL: A compartment for enclosing circuit breakers or other electrical equipment; a single unit of a battery.
34. CIRCUIT: A conductor or that part of an electrical device designed to carry current.
35. CIRCUIT BREAKER (CB): A device for interrupting current flow in a circuit under normal or fault conditions.
1. ACCIDENT PREVENTION TAGS (APTs): Temporary signs or tags that have preprinted instructions and markings used
to:
*Restrict operation or other action so that personnel and or systems and components are protected
*Warn that the tagged system or component is in a condition for test or maintenance activities
*Indicate that the system or component is under the operating jurisdiction of an organizational unit other than the operating agent.
2. AIR CIRCUIT BREAKER: A circuit breaker in which the interruption occurs in air.
3. ALTERNATING CURRENT: That form of electric current that changes in magnitude and polarity in what
is normally a regular pattern for a given time period.
4. AMMETER: An instrument for measuring electric current.
5. AMPERE: The unit of current flow of electricity. One ampere is equal to one coulomb per second flow.
6. APPARENT POWER: For single phase, the current in amperes times the electromotive force in volts equals
the apparent power in volt-amperes. This term is used for alternating current circuits because the current flow is not always in phase with
the electromotive force; hence, amperes times volts does not necessarily give the true power. Apparent power for three-phase circuits
equals volts times amperes times 1.73.
7. AUTHORIZED PERSON: A person that is authorized to receive Work Authorities on circuits and equip-
ment from the Load Dispatcher or their Field Representatives. Certification as an Authorized Person is required in order to hold any form of
Work Authority.
8. AUTOMATIC RECLOSER (ARs): An AR (Auto Recloser) is a reclosing device (relay), or a function of an
IED, that initiates the reclosing of a circuit after it has been opened by a protective relay.
,9. AUTOTRANSFORMER: A transformer in which the primary and secondary have a common winding.
10. AUTOMATIC RECLOSING: A circuit breaker feature that will cause the CB to reclose automatically after
it has relayed.
11. AUTOMATIC TRANSFER SWITCH (ATS): An ATS is a device used to automatically transfer con-nections from
one circuit to another, commonly used for transferring a station service load from a preferred source to an alternate source.
12. BANK: One or more transformers that furnish three-phase power to a load.
13. BANK OF TRANSFORMERS: Any group of transformers connected together with some point on each
winding held in common. It may be for the purpose of voltage transformation or circuit isolation.
14. BARRICADE: A physical obstruction placed to warn against accidental contact with a hazard or restrict entry into a
hazard area. Barricades may be plastic Barricade tape of any color, flags, or any other device that will serve this purpose.
15. BATTERY: A group of several cells connected together as a unit for furnishing electric current.
16. BELT CIRCUITS: Overhead or underground circuits connecting receiving and switching stations together
and through which power can flow in either direction.
17. BID: A request to program complex or supplemental work...usually in advance...on Power System equipment, that
requires a Clearance or OK TO.
18. BLADE: The hinged or moving part of a disconnect through which current flows.
19. BLOCK DIAGRAM: A symbolic diagram; a diagram depicting the distributing stations supplied by a
receiving station as rectangles and all lines or cables connecting them as solid or dashed lines respectively; and usually referred to as a
34.5kV System block diagram.
20. BREAKER: See CIRCUIT BREAKER.
21. BUS: A bus conductor, or group of conductors, which serves as a common connection for several circuits within
, a station or switchyard.
22. BUS TIE: The means by which two separate buses (Bus No. 1 and Bus No. 2) may be electrically connected together
through a set of disconnects and circuit breaker.
23. CABLE: 1. An electrical circuit that is entirely underground is designated as a Cable. 2. The underground portion of a
combination electrical circuit. 3. The type of conductor that is installed underground.
24. CAPACITANCE: The ability of a conductor to store an electric charge.
25. CAPACITIVE REACTANCE: The opposition offered by capacitance to the flow of current and which is
expressed in ohms.
26. CAPACITOR: A device that stores an electric charge; two electrodes or group of electrodes called plates and which are
separated by an insulator or dielectric.
27. CAPACITY: The number of amperes of electric current a conductor, switch, circuit breaker, disconnect, bank, etc., will
carry without becoming overly heated.
28. CB, AIR: A breaker in which the interruption takes place in air.
29. CB, AIR BLAST: A breaker in which the interruption of current is accomplished with a blast of compressed
air supplied from an air compressor system.
30. CB, GAS: A breaker in which the interruption takes place in a pressurized gas chamber, normally SF6.
31. CB, OIL: A breaker in which the interruption takes place in oil.
32. CB, VACUUM: A breaker in which the interruption takes place in a vacuum.
33. CELL: A compartment for enclosing circuit breakers or other electrical equipment; a single unit of a battery.
34. CIRCUIT: A conductor or that part of an electrical device designed to carry current.
35. CIRCUIT BREAKER (CB): A device for interrupting current flow in a circuit under normal or fault conditions.
