ABSTRACT

High-voltage direct current stations have been a major focus area for the study of power system harmonics due to their rectifier and inverter stations. Roughly two decades ago, electronic devices that could handle several kW up to several MW became commercially viable and reliable products. Both the Institute of Electrical and Electronics Engineers and the International Electrotechnical Commission recognize the need to consider the time-varying nature of harmonics when determining harmonic levels that are permissible. Both organizations publish harmonic limits, but the degree to which the various limits can be applied varies widely. A transfer impedance scan predicts how a customer’s harmonic producing load at one location can impact voltage distortions at other locations. In general, to assess the ability of a relatively small current injection to produce a significant voltage distortion at remote locations is the primary goal of every harmonic study.