Comments on active power flow and energy accounts in electrical systems with nonsinusoidal waveforms and asymmetry

Pricing of electric energy is presently based on the value of the integral of the load active power P measured by energy meters. At such a pricing, the electric power utilities waste some revenues for the energy delivered to current harmonic generating customers and/or customers causing current asymmetry. This is because the load generated current harmonics and unbalanced currents cause an increase in the active power loss in the distribution system. At the same time, the customers that do not generate harmonics but are supplied with distorted and/or asymmetrical voltage are billed not only for the useful energy but also for the energy which may cause only harmful effects on their equipment. It is shown in the paper that these two disadvantages of the present tariff in single-phase systems could be eliminated if the energy account based on the value of the integral of the active power of only fundamental harmonic, PI, rather than on the integral of the whole active power P was used. These disadvantages could be eliminated in threephase systems if the energy account is based on the integral of the active power of the positive sequence component of the fundamental harmonic.