Voltage-Distortion Compensation in Electrical Plants Supplying Static Power Converters

Voltage distortion compensation is a problem that must often be tackled in electrical plants supplying nonlinear loads, such as static power converters, both to ensure reliable behavior of apparatus sensible to harmonics and to comply with standard limits. Analysis of the compensation system constituted by harmonic filters and protection reactance is carried out, to clarify their contribution to voltage distortion factor improvement and fundamental project criteria. To this end a study of the current commutation transient, cause of voltage notches and, hence, of voltage distortion, is performed in the presence of filters, and the distortion factor is calculated by means of two separate methods. Comparison between these methods, based on voltage notches and harmonic voltage drop, respectively, and determination of the expressions for estimating the overlap angle after filter insertion allow the influence of filters on the line and the converter to be analyzed.