IEEE 824:2004 pdf free download – IEEE Standard for Series Capacitor Banks in Power Systems
3.23 platform-to-ground communication insulator: An insulator that encloses communication signalpaths between platform and ground level.
3.24 power capacitor (capacitor, capacitor unit): An assembly of dielectric and electrodes in a container(case), with terminals brought out, that is intended to introduce capacitance into an electric power circuit.
3.25 protective device: A bypass gap, varistor, or other device that limits the voltage on the capacitor seg-ment or subsegment to a predetermined level when overcurrent flows through the series capacitor.
3.26 protective level: The magnitude of the maximum peak of the power-frequency voltage allowed by theprotective device during a power system fault. The protective level may be expressed in terms of the actualpeak voltage across a segment or subsegment or in terms of the per unit of the peak of the rated voltageacross the segment or subsegment.
NOTE—See 5.5.
3.27 reinsertion: The restoration of load current to the series capacitor from the bypass path.
3.28 reinsertion current: The transicnt current,power-frequency current, or both,flowing through theseries capacitor bank after the opening of the bypass path.
3.29 reinsertion voltage: The transient voltage, steady-state voltage, or both, appearing across the seriescapacitor after the opening of the bypass path.
3.30 series capacitor bank: A three-phase assembly of capacitor units with the associated protectivedevices,discharge current limiting reactors， protection and control system, bypass switch, and insulatedsupport structure that has the primary purpose of introducing capacitive reactance in series with an electriccircuit.
3.31 series capacitor installation: An installed series capacitor bank complete with disconnect switches.
3.32 segment: A single-phase assembly of capacitor units and an associated protective device,dischargecurrent limiting reactor, protection and control functions， and one phase of a bypass switch.Segments arenot normally separated by isolating disconnect switches. More than one segment can be on the same insu-lated platform.
NOTE—See Figure 1.
3.33 subsegment: A portion of a segment that includes a single-phase assembly of capacitor units and anassociated protective device, discharge current limiting reactor, and selected protection and control func-tions, but does not have a dedicated bypass switch.
NOTE—See Figure 1.
3.34 switching step: A three-phase assembly that consists of one segment per phase,with a three-phaseoperating bypass switch for bypassing or inserting the capacitor segments. This is sometimes referred to as acapacitor module.
NOTE—See Figure l.
3.36 trigger circuit: The part of the bypass gap that initiates the sparkover of the bypass gap at a specifiedvoltage level or by external command.
3.37 valve element (of a varistor unit): A single nonlincar resistor disc used in a surge arrester or varistorunit.
3.38 varistor: An assembly of varistor units that limit overvoltages to a given value. In the context of seriescapacitor banks，the varistor is typically defined by its ability to divert fault current around the seriescapacitor units,limiting the voltage to a specified protective level while absorbing energy.The varistor isdesigned to withstand the temporary overvoltages and continuous operating voltage across the seriescapacitor units.
3.39 varistor coordinating current: The varistor current magnitude associated with the protective level.The varistor coordinating current waveform is considered to have a virtual front time of 30 us to 50 us. Thetail of the waveform is not significant in establishing the protective level voltage.
3.40 varistor energy rating: The maximum energy the varistor can absorb within a short period of timewithout being damaged due to thermal shock or thermal runaway during the subsequent applied voltage.This rating is based on the duty cycle defined by the purchaser. This is the usable rating after taking intoaccount factors such as current sharing among parallel columns. The additional energy absorption capabilityof the spare units is not normally included in this rating.
3.41 varistor maximum continuous operating voltage (MCOV):The rated rms voltage of the capacitorsegment that the varistor is connected across.
3.42 varistor unit: A single insulated enclosure containing one or more valve elements in series and possi-bly in paralle1.
3.43 voltage-triggered bypass gap: A bypass gap that is designed to spark over on the voltage that appearsacross the gap terminals. The sparkover of the gap is normally initiated by a trigger circuit set at a specifiedvoltage level.A voltage-triggered bypass gap may be used for the primary protection of the capacitor andmay spark over during external as well as internal faults.