Harmonic cost allocation: a difficult task

Harmonic allocation is a function of the harmonic currents magnitudes and spectrum of the injected currents, nevertheless, the allocation goes one step further and deals with the fair distribution of the cost of services and equipment needed to maintain a reasonable harmonic free electromagnetic environment. The difficulties arise from the fact that the correct approach to the allocation of the expenses caused by harmonics depends on the understanding of the physical mechanisms of harmonics generation and propagation, as well as the use of economical models true to the social and economical interactions among the electric utilities, customers, and other parties sharing the right of way or the same electromagnetic environment. This paper points out some of the technical difficulties that are encountered by a power quality engineer or a counsel in charge of drafting the terms of a contract meant to provide rules agreeable to customers that use nonlinear loads (NLs) and to the providers of electric energy. Such rules are meant to limit the amount of electromagnetic pollution caused by NLs and to allow the correct and fair recovery of the capital invested in mitigation equipment as well as the costs of useful life lost, additional energy lost through RI², eddy currents, hysteresis and dielectric losses caused by current and voltage harmonics. Moreover, the same rules are meant to provide all the customers connected at the same network electric energy with quality continuously maintained according to the proper engineering practice