Automated Protection System
A system of protective devices that automatically opens a circuit when the current exceeds a set limit.

Capacitor Switching Transients
A one-cycle disturbance that occurs when a substation capacitor bank is initially switched on.

Circuit Breaker (or fuse)
A protective device located on an electrical circuit to interrupt the flow of abnormally large currents. A circuit breaker is the most common means of providing overload and fault protection for customers and utilities.

Conductor
A substance or body that allows an electrical current to pass continuously along it. Electrical equipment receives power through electrical conductors.

Control System
A circuit that controls the operation of a device, such as the start/stop circuit on a motor starter.

Electronic Equipment
Equipment constructed with electronic chips. Common examples include TVs, radios, stereos and computers.

Electrical Fault
An abnormal connection causing current to flow from one conductor to ground or to another conductor. A fault may be corrected automatically or may lead to a voltage sag or power outage.

Electrical Meter
A device for measuring an electrical circuit, such as the watt-hour meter on a house. Meters are generally used to measure voltage or current, but can also be used to measure power.

Electrical Noise
An unwanted electrical signal that produces an undesirable effect.

Electrical Panel
A box or panel where circuit breakers or fuses are located.

Electro Magnetic Interference (EMI)
Any electromagnetic disturbance, phenomenon, signal or emission that causes or can cause an undesired response, malfunction, or degradation of performance of electrical and electronic equipment.

Electronic Ballast
A newer type of ballast commonly used for fluorescent lighting. A ballast contains an electronic circuit that produces the voltage needed for lighting.

Energized Equipment
Equipment that has voltage potential available within it, such as an electrical panel when the main circuit breaker is switched on.

Fault
See Electrical Fault.

Fault Protection System
A system composed of devices that are able to sense abnormal current flow and prevent it. PGE’s fault protection system includes circuit breakers, fuses, reclosers and switches.

Generator
Any device that converts one form of energy (mechanical, chemical or heat) into electrical energy and produces either direct or alternating current.

Ground Conductor
A conductive path used to connect equipment to a grounding electrode. A low impedance path for fault current to follow to help facilitate the operation of fault protection.

Harmonic Distortion
Distortion of an electrical sine wave caused by the power supplies of certain electronic devices. A mathematical representation of a distortion of a pure sine waveform.

Line Interactive UPS
A type of uninterruptible power supply (UPS) that is in standby mode most of the time but contains a transformer that helps condition and adjust the voltage until the voltage exceeds a set limit. If the voltage limit is exceeded, the UPS can support the load until the voltage returns to within the limits or the battery is drained. See the Line Interactive UPS device available through PGE. It’s model number ES800C.

Line Reactors
An inductor, or coiled conductor, that opposes any changes in the current flow.

Main Circuit Breaker
A circuit breaker that can interrupt all power in a facility.

Mitigation Equipment
Equipment, such as surge suppressors and uninterruptible power supplies (UPS), which prevents unusual electrical disturbances from affecting equipment.

Nameplate Rating
The electrical specifications provided by the manufacturer of a device.

National Electric Code (NEC)
NEC and National Electrical Safety Code (NESC) are consensus standards formulated from input by the entire electrical industry. The NEC is designed for the practical safeguarding of persons and property from hazards arising from the use of electricity. The scope of the NEC is limited to all electrical construction up to the point where the connection is made to the electrical utility conductors. This point is also known as the “Point of Common Coupling (PCC).” The NESC covers all electrical construction on the utility side of the PCC.

Nominal Voltage
A standard value assigned to a circuit for the purpose of conveniently designating its voltage class.

Online (double conversion) UPS
A type of uninterruptible power supply (UPS) that is constantly converting the incoming power from AC to DC and then inverting DC back to AC. This double conversion process prevents power disturbances from reaching protected loads. The UPS batteries will support the load if conditions exceed a set limit.

Plug and Play UPS
A type of small uninterruptible power supply (UPS) that can be plugged into an existing receptacle. See PGE’s selection of UPS products.

Power
The rate of doing work, usually measured in kilowatt-hours.

Power Spike
See Power Surge.

Power Surge
A sudden, sharp increase in the voltage or current lasting less than one cycle.

PowerBack Contractors
Electrical contractors certified by PGE that are available within 24 hours of receiving a call to restore a customer’s electrical service in the event of damage. A PowerBack Contractor can be reached 24 hours a day, seven days a week to schedule home electrical repairs. See our list of PowerBack Contractors.

Radio Frequency Interference (RFI)
An unwanted electrical signal that travels through the air or follows the path of a conductor and interferes with communications. Some common causes of RFI include light dimmers, fluorescent lights, variable frequency drives, and computers.

Receptacle
A socket or outlet into which a plug can be inserted to make an electrical connection.

Recloser
A protective device that automatically opens a circuit when the current exceeds a set limit. It then attempts to close a set number of times after a fixed time delay.

Sag
See Voltage Sag.

Single Phased
One of the phases of a three-phase service that is not available.

Single Phase Events
An electrical disturbance that affects only one phase (electricity is generated in three phases) of a two- or three-phase system.

Standby UPS
A type of uninterruptible power supply (UPS) that remains in standby mode offering little or no power conditioning unless the voltage exceeds a set limit. If the voltage limit is exceeded, the UPS can support the load until the voltage returns to within the limits or the battery is drained. See the Standby UPS device available through PGE. It’s model number VS575C.

Surge Arrester
See Surge suppressor.

Surge Damage
The failure of a device due to a sudden increase in the voltage or current.

Surge Suppression
A means for limiting, or suppressing, surge voltages.

Surge Suppressor
A protective device for limiting surge voltages on equipment by discharging or bypassing the surge current to ground. See the selection of surge suppressor products available through PGE.

Transfer Switch
A device for transferring one or more loads from one power source to another.

Transient Voltage Surge Suppressor (TVSS)
See Surge suppressors.

Uninterruptible Power Supply (UPS)
An electronic device that automatically provides power from a battery when the voltage exceeds a set limit. The three most common types of UPS are: Standby UPS, Line Interactive UPS, and Online (double conversion) UPS. See the selection of UPS products available through PGE.

Variable Frequency Drive (VFD)
An electronic device that controls the speed and direction of a motor by changing the voltage and frequency of the power to the motor.

Voltage Distortion
Any distortion in the voltage from a perfect sine wave.

Voltage Rating
The voltage classification of a device.

Voltage Sag
A decrease in the RMS (root mean square), or effective voltage measured as a percent of the nominal voltage.

Whole House Surge Suppressor
A type of surge suppressor that is designed to protect the whole house from power surges originating on the utility distribution system. Separate protection devices are required for telephone and cable systems to protect against surges traveling through the telephone or cable. See the Whole House Surge Protection Package available through PGE.