506 Siemens Energy Sector t Power Engineering Guide t Edition 7.0 Glossary 11 Siemens Energy Sector t Power Engineering Guide t Edition 7.0 507 Glossary A Circuit-breaker A mechanical switching device, capable of making, carrying and breaking currents under Air circuit-breaker A –> circuit-breaker in which the contacts open normal circuit conditions and also making, and close in air at atmospheric pressure. carrying for a specified time and breaking Air-insulated High voltage substation where all live parts are currents under specified abnormal circuit outdoor switchyards insulated by air and are not covered. AIS are conditions such as those of short-circuit. of open design (AIS) always set up in a fenced area with access for Common The Common Information Model (CIM) is an authorized personal only. information model open standard that defines how managed Ambient Temperature (measured under specific (CIM) elements in an IT environment are represented temperature conditions) of the air surrounding an item of as a common set of objects and relationships electrical equipment. The ambient temperature between them. This is intended to allow affects heat dissipation, which can make it consistent management of these managed necessary to reduce the –> rated current. elements, independent of their manufacturer or provider. Auto-reclosing (of a The operating sequence of a mechanical mechanical switching device whereby, following its Contactor Load breaking device with a limited short- switching device) opening, it closes automatically after a circuit making or breaking capacity, used for predetermined time. high switching rates. Automatic multiple An automatic reclosing repeated two or three Continuous Function A Siemens engineering tool that offers shot reclosing times (usually not more) if it is not successful. Chart (CFC) graphical interconnection and parameterization of off-the-shelf or user-defined function blocks B to solve sophisticated continuous control applications –> SFC. Back-up protection Interaction of two carefully matched overcurrent protective devices connected in Current limiting Ability of an overcurrent protective device (fuse series at points where, in the event of a fault, a or circuit-breaker) to reduce the peak current in single device is not capable of switching the a circuit beyond the value of the peak short- prospective short-circuit current. If a circuit current expected on the basis of the correspondingly high short-circuit current circuit constants (R, L), by opening and clearing occurs, the back-up overcurrent protective the fault in a sub-cycle time frame. device relieves the next downstream Current-limiting A circuit-breaker with a break-time short overcurrent protective device, thus preventing circuit-breaker enough to prevent the short-circuit current it from being overloaded. reaching its otherwise attainable peak value Blackout Complete power outage. Current transducer Transducer used for the measurement of an Breaking operation Interruption of an electric circuit as a result of alternating current. the contact members of a switching device Current transformer Type of instrument transformer designed to being opened. (CT) provide a current in its secondary winding Breaking capacity Highest current a switching device is capable of proportional to the alternating current flowing breaking under specific conditions. in its primary. CTs facilitate the safe measurement of large currents, often in the Busbar A low impedance conductor, to which several presence of high voltages. The current electric circuits can be connected separately. transformer safely isolates measurement and Busbar trunking Extended enclosed busbars, equipped with control circuitry from the high voltages system outgoing points for supplying machines and typically present on the circuit being measured. other loads with power via variable tap-off D units. DCF77 A longwave time signal and standard-frequency Bushing Device that enables one or several conductors radio station. The transmitted data repeats to pass through a partition such as a wall or a each minute the current date and time, a leap tank and insulate the conductors from it. second warning bit, a summer time bit, a C primary/backup transmitter identification bit, and several parity bits. The callsign DCF77 Capacitor voltage A –> voltage transformer comprising a stands for D=Deutschland (Germany), C=long transformer (CVT) capacitor divider unit and an electromagnetic wave signal, F=Frankfurt, 77=frequency: unit designed and interconnected so that the 77.5 kHz. secondary voltage of the electromagnetic unit is substantially proportional to the primary Dead tank circuit- A –> circuit-breaker with interrupters in an voltage, and differs in phase from it by an angle breaker earthed metal tank. which is approximately zero for an appropriate Dielectric strength Capability of an electrical component to direction of the connections. withstand all voltages with a specific time CAPEX Capital expenditures of an enterprise for fixed sequence up to the magnitude of the assets, e.g. means of production, buildings etc. corresponding withstand voltages. These can 11 –> OPEX. be operating voltages or higher-frequency voltages caused by switching operations, earth Continuous –> Kaizen faults (internal overvoltages) or lightning improvement strikes (external overvoltages). process (CIP) 508 Siemens Energy Sector t Power Engineering Guide t Edition 7.0 Glossary Demilitarized zone A subnetwork between an organization’s LAN G (DMZ) and an external network, usually the internet. The hosts in the DMZ contain and provide all Gas-insulated Indoor and outdoor switchgear of compact external services of an organization such as switchgear (GIS) design and small dimensions for substations up e-mail or web server, but are not allowed to to 550 kV to be installed in urban or industrial connect directly to the internal LAN. loadcenters. All components are housed in earthed metal enclosures filled with sulfur Disconnector Mechanical switching device which, in the hexafluoride (SF ) gas for insulation. (isolator) open position, disconnects all the poles of an 6 electric circuit. Disconnectors are used for no- Gas-insulated Transmission lines composed of pipes that load closing and opening operations, e. g. to transmission line house conductors in highly insulative sulfur isolate downstream devices so they can be (GIL) hexafluoride (SF6) gas, which have high load- worked on. transfer capacity. Distributed Generation units, such as PV panels, wind Generic Interface A set of common services used for enterprise generation units turbines, or cogeneration units, which are Definition integration in the utility industry, defined in IEC connected to the LV or MV distribution standard IEC 61970. network. GPRS A packet oriented mobile data service available E to users of –> GSM. Grid-connected A photovoltaic system in which the Ear and mouth A technology in voice over IP (VoIP) that uses a photovoltaic system photovoltaic array acts like a central generating (E&M) traditional telephone handset with an plant, supplying power to the grid. earphone (or earpiece) for listening to incoming audio and a microphone (or Grid power flow A concept in system technology within the –> mouthpiece) for transmitting audio. Calls using controller (GPFC) FACTS family of devices that provides an an E&M interface can be made from, received economic solution for the purpose of power from, or disconnected by a private branch transmission between two or more adjacent AC exchange (PBX) as well as from a VoIP-capable systems. The AC systems can be either computer. The term ear and mouth interface is synchronous or nonsynchronous. The most sometimes used as a synonym for a telephone proper power rating is between 10 MW and handset itself, or for a headset-and-microphone 300 MW, although higher ratings are also combination that allows hands-free operation. achievable. Earth fault Occurrence of an accidental conductive path GSM A worldwide standard for mobile phones. between a live conductor and the earth. H Earthing switch Mechanical switching device for earthing parts of an electric circuit, capable of withstanding Harmonics The sinusoidal (harmonic) oscillations in the for a specified duration electric currents under Fourier analysis of non-sinusoidal, periodic abnormal conditions such as those of short- oscillations that oscillate at a frequency which circuit, but not required to carry electric current is an integer multiple of the fundamental (= under normal conditions of the electric circuit. system) frequency. The amplitudes of harmonics are considerably smaller than the ECR A zero boron glass that is free of added fundamental frequency. fluorides. It conforms to ASTM D578-1999 specification for E glass. It combines the High voltage In general a set of voltage levels in excess of –> electrical and mechanical properties of E glass low voltage (< 1 kV). In a more restrictive sense with superior inherent corrosion resistance. HV is used for voltage levels typically used for ECR glass fiber is an electrical grade corrosion bulk transmission of electricity (> 60 kV). resistant glass fiber. HTTP/HTTPS The hypertext transfer protocol/hypertext F transfer protocol secure is a communications protocol for the transfer of information on the Feeder An electric line originating at a main substation intranet and the World Wide Web; HTTPS is and supplying one or more secondary widely used for security-sensitive substations. communication. Flexible AC A power electronic based