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Apparent power is the product of the RMS values of voltage and current. Apparent power is taken into account when designing and operating power systems, because although the current associated with reactive power does no work at the load, it still must be supplied by the power source.
The volt-ampere (SI symbol: VA, [1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit.It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). [2]
The power factor is defined as the ratio of real power to apparent power. As power is transferred along a transmission line, it does not consist purely of real power that can do work once transferred to the load, but rather consists of a combination of real and reactive power, called apparent power.
In an electrical grid, the short circuit ratio (or SCR) is the ratio of: the short circuit apparent power (SCMVA) in the case of a line-line-line-ground (3LG) fault at the location in the grid where some generator is connected, to: the power rating of the generator itself (GMW).
Power ratings are usually given in watts for real power and volt-amperes for apparent power, although for devices intended for use in large power systems, both may be given in a per-unit system. Cables are usually rated by giving their maximum voltage and their ampacity . [ 4 ]
For each sample, the voltage is multiplied by the current at the same instant; the average over at least one cycle is the real power. The real power divided by the apparent volt-amperes (VA) is the power factor. A computer circuit uses the sampled values to calculate RMS voltage, RMS current, VA, power (watts), power factor, and kilowatt-hours.
power rating is specified in terms of apparent power (KVA or MVA), since the exact power factor will be determined by the external factors; [5] power factor (PF) is the nominal power factor for other ratings; usually PF = 0.8; [5] insulation class (B, F, H) for the primary coil. Typical value is F, although older generators might use class B; [5]
electrical (real power to apparent power) Power number: N p ... fluid mechanics, power consumption by rotary agitators; resistance force versus inertia force)