Adaptive compensation of nonlinear loads in power systems

Abstract

The objective of this work is to accommodate the effects of the harmonic signals in power distribution systems. Adaptive output predictors are used to estimate the future values of the load currents based on a finite-memory of past input-output values. The unknown time varying magnitudes and phase angles of harmonics are modeled as the adaptively estimated parameters. Having the predicted load current available in advance, its harmonic content can be identified and the compensation can be done at the correct time with minimum amount of mismatch between the load current and the compensated current. Because of the nonlinear nature of the loads, the harmonics vary continuously. Therefore, the future values of the load current are obtained using adaptive prediction with a specified number of time steps ahead that will be sufficient to carry out the needed compensation. Results of simulation with one, two, and three step ahead predictions are presented.