Statistical standards and pollution estimation of harmonics in a power system

Harmonic distortion has always been a critical issue existing in an electrical power feeder of a utility or customer, and many harmonic administration standards have been defined. As far as these are concerned, the immediately measured harmonics are always used to judge whether a user is illegal in harmonic limits or not. However, harmonics are changeable with load condition and system structure, therefore, when the measured data is out of order, the illegal judgement may not be objective and it may be easy to resolve the dispute. So we must exclude those bad data, and statistical harmonic limits must be reasonable. In this paper, a bad data detecting technique is used to process the measured harmonic data, as well as a statistical harmonic limit standard being recommended by considering the periodic characteristics of harmonics. A developed microcomputer-based instrument system is also used to estimate the harmonic pollution of a high voltage feeder by the statistical harmonics limit standard and the bad data processing algorithms.