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An important property of three-phase power is that the instantaneous power available to a resistive load, = =, is constant at all times.Indeed, let = = To simplify the mathematics, we define a nondimensionalized power for intermediate calculations, =
Then, the real numbers of impedances and voltages can be substituted into the per-unit calculation definition to get the answers for the per-unit system. If the per-unit values are known, the real values can be obtained by multiplying by the base values. By convention, the following two rules are adopted for base quantities:
Typically, the inductive load will be rated at a numeric value 75% that of the corresponding resistive load such that when applied together a resultant 0.8 power factor load is provided. That is to say, for each 100 kW of resistive load, 75 kVAr of inductive load is provided. Other ratios are possible to obtain other power factor ratings.
In general, engineers are interested in the active power averaged over a period of time, whether it is a low frequency line cycle or a high frequency power converter switching period. The simplest way to get that result is to take the integral of the instantaneous calculation over the desired period:
Kvar or KVAR may refer to: Kvar, a character from the video game Tales of Symphonia; Kilovolt-amperes reactive, thousand Volt-ampere reactive, a unit of reactive power; KVAR (FM), a radio station (93.7 FM) licensed to Pine Ridge, South Dakota; KPNX, a television station (Channel 12) licensed to Mesa, Arizona, which formerly used the call sign KVAR
Power Quality Analyzers, often referred to as Power Analyzers, make a digital recording of the voltage and current waveform (typically either one phase or three phase) and accurately calculate true power (watts), apparent power (VA) power factor, AC voltage, AC current, DC voltage, DC current, frequency, IEC61000-3-2/3-12 Harmonic measurement ...
In the context of domestic PV installations, the kilowatt (symbol kW) is the most common unit for nominal power, for example P peak = 1 kW. Colloquial English sometimes conflates the quantity power and its unit by using the non-standard label watt-peak (symbol W p), possibly prefixed as in kilowatt-peak (kW p), megawatt-peak (MW p), etc.
IDC—Interchange Distribution Calculator (electricity) IEA—International Energy Agency (Paris) IEC—International Electrotechnical Commission; IEM—Internal electricity market (electricity) IEEE—Institute of Electrical and Electronics Engineers; IEPE—Institute of Energy Policy and Economics (France) IER—Incremental Energy Rate