Electrical Power conversion efficiency (Power factor)
Technical losses
Power in electricity networks is defined by real power: P, as the capacity of the system to do work measured in watts (W) and reactive power: Q, as the power that flows back to the source from inductors and capacitors measured in Volt Ampere reactive (VAr) and apparent power (S), as the scalar product of voltage and current measured in Volt Ampere (VA).
Power factor is the ratio of the real power to the apparent power: P/S. As it is less than unity, the current has to increase to deliver the required amount of real power, which results in energy losses. This has historically been an issue for commercial and industrial customer installations, where most motor loads or power electronic loads were seen but developments in domestic power electronics and heat pumps mean that is occurring more on the low voltage networks.
It is common practice amongst DNOs to incorporate power factor losses in the wider variable losses category.
