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In direct current (DC) circuits, this product is equal to the real power, measured in watts. [3] The volt-ampere is dimensionally equivalent to the watt: in SI units, 1 V⋅A = 1 W. VA rating is most used for generators and transformers, and other power handling equipment, where loads may be reactive (inductive or capacitive).
If θ is the phase angle between the current and voltage, then the power factor is equal to the cosine of the angle, : | | = | | Since the units are consistent, the power factor is by definition a dimensionless number between -1 and 1. When the power factor is equal to 0, the energy flow is entirely reactive, and stored energy in the ...
Electric power is the rate of transfer of electrical energy within a circuit.Its SI unit is the watt, the general unit of power, defined as one joule per second.Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.
In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit).
Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity, [1] is the intended full-load sustained output of a facility such as a power station, [2] [3] electric generator, a chemical plant, [4] fuel plant, mine, [5] metal refinery, [6] and many others.
This gives a phase-to-phase voltage of 400 volts wye service and a single-phase voltage of 230 volts between any one phase and neutral. In the UK a typical urban or suburban low-voltage substation would normally be rated between 150 kVA and 1 MVA and supply a whole neighbourhood of a few hundred houses.
All the SI prefixes are commonly applied to the watt-hour: a kilowatt-hour is 1,000 Wh (kWh); a megawatt-hour is 1 million Wh (MWh); a milliwatt-hour is 1/1,000 Wh (mWh) and so on. The kilowatt-hour is commonly used by electrical energy providers for purposes of billing, since the monthly energy consumption of a typical residential customer ...
In general, losses are estimated from the discrepancy between power produced (as reported by power plants) and power sold; the difference constitutes transmission and distribution losses, assuming no utility theft occurs. As of 1980, the longest cost-effective distance for DC transmission was 7,000 kilometres (4,300 miles).