July 3, 2011

Electrical Engineering Terms - P

  • Packet - When data is ready to be transmitted it is divided into pieces called packets. These packets contain information about which computer sent the data and where the data is going.
  • Pad Mounted Transformer - A transformer that is mounted on a pad (usually concrete or polycrete) that is used for underground service. Pad mounted transformers are available in single phase and three phase configurations.
  • Parallel Connection - In the case of DC circuits, a way of joining two or more electrical devices or wires by connecting positive leads and negative leads together.
  • Parametric Conjuctive Test - A conjunctive test that ascertains the range of values of each parameter for which the test meets specific performance requirements.
  • Parking Bushing - A bushing that is designed to accept a 200a elbow. Parking bushings are used to "Park" a hot cable that is terminated with a 200 Amp rated elbow.
  • Parking Stand - A metal bracket, usually made of steel, that is used to support a parking bushing that in turn is used to "Park" a medium voltage cable that is terminated with an 200 Amp rated elbow. Parking Stands are usually furnished mounted to the front panel of 200
  • Parkway - Sometimes referred to as a rating for Grade Level Boxes or Covers rating. See "Incidental Light Traffic".
  • Pasted Plate (Battery) - Paste in which the active material is applied as a paste to a conductive grid.
  • PC Card - A credit card-sized peripheral that plugs into personal computers to expand RAM memory, add a modem, network card, hard drives, and other various PC devices. Three types of card have been standardized by the PCMCIA Type I, Type II, and Type III. They have
  • PCB - Printed circuit board.
  • PCC - Point of Common Coupling.
  • PCI - Peripheral Component Interconnect. Self-configuring PC local bus.
  • PCMCIA - Personal Computer Memory Card International Association. Trade association founded in 1989 to establish standards for expansion cards for portable computers (See PC Card).
  • PE - Polyethylene. PE is a thermoplastic wire and cable insulating material that is also used for cable jacketing.
  • Peak to Peak - The amplitude of the ac wave form from its positive peak to its negative peak.
  • PED - Power Electronic Device.
  • Pedestrian Loading - Refers to a grade level Reinforced Polymer Concrete or Fiberglass Reinforced Plastic Box or Cover loading applied by pedestrian traffic.
  • Pedestrian Walkway (Lighting) - A public walk for pedestrian traffic not necessarily within the right-of-way for vehicular traffic. Included are skywalks (pedestrian overpasses), subwalks (pedestrian tunnels), walkways giving access to parks or block interiors and mid-block street cros
  • PF - Power Factor
  • Phase Angle - The angular displacement between a current and voltage waveform, measured in degrees or radians.
  • Phase Angle Transducer - A transducer used for the measurement of the phase angle between two a.c. electrical quantities having the same frequency.
  • Phase Rotation - Phase rotation defines the rotation in a Poly-Phase System and is generally stated as "1-2-3", counterclockwise rotation. Utilities in the United States use "A-B-C" to define their respective phase names in place "1-2-3". However some refer to their rot
  • Photovoltaic - Refers to the conversion of light into electricity.
  • Photovoltaic Array - An interconnected system of photovoltaic modules that function as a single electricity producing unit. The modules are assembled in a discrete structure, with common mechanical support or mounting. In small systems, an array can consist of a single modu
  • Photovoltaic Cell - The smallest semiconductor element within a photovoltaic module to perform the immediate conversion of light into electrical energy (DC Voltage and DC Current).
  • Photovoltaic Concentrator - A Photovoltaic module that uses optical elements to increase the amount of sunlight incident on a Photovoltaic cell. Concentrating arrays must track the sun. Efficiency is increased, but lifespan is decreased because of the high heat.
  • Photovoltaic Conversion Efficiency - The ratio of electric energy produced by a photovoltaic device to the energy from sunlight incident unpn the cell.
  • Photovoltaic Efficiency - The ratio of electric power produced by a cell at any instant to the power of the sunlight striking the photovoltaic cell. This is typically 9% to 14% for commercially available cells.
  • Photovoltaic Module - The smallest environmentally protected, essentially planar assembly of solar cells and ancillary parts, such as interconnections, terminals and protective devices such as diodes intended to generate dc power under unconcentrated sunlight. The structural
  • Photovoltaic Panel - Often used interchangeably with Photovoltaic Module. Especially in one-module systems , but more accurately used to refer to a physically connected collection of modules (i.e., a laminate string of modules used to achieve a required voltage and current).
  • Photovoltaic Stand-Alone System - An autonomous or hybrid photovoltaic system not connected to a grid. The system may or may not have storage but most have require a battery.
  • Photovoltaic System - A complete set of components for converting sunlight into electricity by the Photovoltaic process, including the array and balance of system devices.
  • Pick up ratio - The ratio of the limiting values of the characteristic quantity at which the relay resets and operates. This value is sometimes called the differential relay.
  • Pick-up - A relay is said to 'pick-up' when it changes from the de-energized position to the energized position.
  • Pilot Channel - A means of interconnecting between relaying points for the purpose of protection.
  • Pilot Line - A cord or rope used to pull a heavier rope that will be used to pull a conductor into place.
  • Ping - Ping is a computer program that sends a packet over the internet to another computer to see if the remote computer is still responding. If the ping returns to the sending computer the remote computer is still connected.
  • Plante Plate (Battery) - Plate made of pure lead.
  • Plate (Battery) - The electrode of a cell consisting of a current collector and a positive or negative active material.
  • PLC - Programmable Logic Controller. A specialized computer for implementing control sequences using software.
  • Plug Setting Multiple - A term used in conjunction with electromechanical relays, denoting the ratio of the fault current setting of the relay.
  • Pocket Current Transformer - A round or toroidal core transformer mounted on bushings of power transformers, bulk oil circuit breaker, and other dead tank circuit breakers. These transformers are placed in pockets of these elements they are mounted on where the pocket length is measu
  • Point of Common Communication - The interface between an in-plant network containing embedded generation and the utility distribution network to which the in-plant network is connected.
  • Polarity - 1) The electrical Term used to denote the voltage relationship to a reference potential (+). 2) With regard to Transformers, Polarity is the indication of the direction of the current flow through the high voltage terminals with respect to the direction of current flow through the low voltage teminals.
  • Pole Spacing (Lighting) - (ILL x CU x LLF)/(AMF x RW)
  • Polycrystalline - See "Multi Crystalline".
  • Polyethylene - A thermoplastic material composed of ethylene polymers. Polyethylene has excellent electrical and mechanical properties and is used an insulating material in cable.
  • Polymer Concrete - Also referred to as Reinforced Polymer Mortar (RPM). Polymer Concrete material consists of calcareous and siliceous stone, glass fibers and thermoses polyester resin. Polymer concrete can be used in the manufacture of equipment pads, grade level boxes an
  • Polyphase - A polyphase system is a means of distributing alternating current electrical power. Polyphase systems have two or more energized electrical conductors carrying alternating currents with a definite time offset between the peak amplitudes of the wave in eac
  • Polyvinyl Chloride - Polyvinyl Chloride. PVC, a thermoplastic compound, is a commonly used Wire and Cable insulation and jacketing material.
  • Port - In networking, a server's various functions, such as managing FTP traffic or maintaining the DNS list, are each assigned a virtual address called a port. Any requests for that function are sent to the port address.
  • Port Forwarding - This allows a computer external to a secured network, access a computer on the network through the mapping of a port on the network's firewall to a port on a specified computer.
  • Pot - 1) Slang for an overhead transformer. 2) Short for "Potential".
  • Potential - The voltage in a circuit. Reference is usually to the AC Voltage.
  • Potential Transformer - A transformer used to lower the voltage at a set ratio so that the voltage can be measured by instruments and meters at a safe representative level.
  • Pothead - Slang for a device used to transition an overhead conductor to underground. Potheads are normally porcelain and have been largely replaced with non-ceramic, synthetic rubber, terminators of the type manufactured by Thomas & Betts Elastimold.
  • POW - Point-on-Wave. Point-on-wave switching is the process to control moment of switching to minimize the effects (inrush currents, over-voltages).
  • Power - Rate at which energy is released or consumed, expressed in watts.
  • Power Electronics Device - An electronic device (e.g. thyristor or IGBT) or assembly of such devices (e.g. inverter). Typically used in a power transmission system to provide smooth control of output of an item of plant.
  • Power Exchange - See California Power Exchange.
  • Power Factor - The ratio of energy consumed (watts) versus the product of input voltage (volts) times input current (amps). In other words, power factor is the percentage of energy used compared to the energy flowing through the wires. Adding capacitors to the system
  • Power Line Carrier Communication - A mean of transmitting information over a power transmission line by using a carrier frequency superimposed on the normal power frequency.
  • Power Marketer - An entity that takes title to electric power and then resells the power to end-use customers. This "middleman," which acts for itself in negotiating contracts, purchases, or sales of electrical energy, is required to meet two FERC tests to be certified as
  • Power Transformer - A large transformer, generally larger than 1,000 kVA in capacity.
  • PPP - Point-to-Point Protocol. PPP is the internet standard for serial communications. PPP defines how modem connection exchanges data packets with other systems on the internet.
  • PPTP - Point-to-Point Tunneling Protocol. PPTP is a protocol that allows secure transmission of data in TCP/IP packets. PPTP protocols are used to carry secure communications over Virtual Private Networks that use public phone lines.
  • Prohibited Approach Boundary - An approach limit at a distance from an exposed live part within which work is considered the same as making contact with the live part.
  • Protected Zone - The portion of a power system protected by a given protection system or a part of that protection system.
  • Protection Equipment - The apparatus, including protection relay, transformers and ancillary equipment, for use in a protection system.
  • Protection Relay - A relay designed to initiate disconnection of a part of an electrical installation or to a warning signal, in the case of a fault or other abnormal condition in the installation. A protection relay may include more than one electrical element and accessor
  • Protection Scheme - The coordinated arrangements for the protection of one or more elements of a power system. A protection scheme may compromise several protection systems.
  • Protection System - A combination of protection equipment designed to secure, under pre-determined conditions, usually abnormal, the disconnection of an element of a power system, or to give an alarm signal, or both.
  • Protective Device Numbers, ANSI - 2 Time-delay, 21 Distance, 25 Synchronism-check, 27 Undervoltage, 30 Annunciator, 32 Directional power, 37 Undercurrent or underpower, 38 Bearing, 40 Field, 46 Reverse-phase, 47 Phase-sequence voltage, 49 Thermal, 50 Instantaneous
  • Protocol - Protocols are communication standards set to facilitate the many connections made by computers via modems and other digital connections. Some protocols are PPP, TCP/IP, SLIP, and FTP.
  • Proxy Server - A system that caches items from other servers to speed up access. On the web, a proxy first attempts to find data locally, and if it is not available, obtains it from the remote server where the data resides permanently.
  • PS (Lighting) - Pole Spacing
  • psi - Pounds per square inch
  • PSTN - Public Switched Telephone Network is the concentration of the world's public circuit-switched telephone networks. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital, and now includes mobile as well as fixe
  • PT - See "Potential Transformer".
  • PUC - Public Utility Commission
  • Pull - A noun referring to the installation of one or more cables.
  • Pull Tension - The tension in pounds or kilograms required to pull a cable or wire into a duct or conduit or into an overhead location.
  • Pulling - The act of installing one or more cables.
  • PV - See "Photovoltaic"
  • PVC - Polyvinyl chloride, a common thermoplastic insulation and jacketing material used to manufacture building wire and other types of wire and and cable. It is also used in the manufacture of plastic conduit.
  • PX - See California Power Exchange.




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