Flicker control in mains with distributed generation plants

Abstract

The use of distributed generation (DG) plants in power supply systems is a rapid development line. However, the impact of DG on power quality is multivalued. On the one hand, the presence of DG allows to reduce voltage losses. On the other hand, a phenomenon called flicker and associated with rapid voltage fluctuations is possible. This effect is usually manifested at an abrupt voltage drop in the DG generator connection unit. The processes taking place in the network when flicker occurs in networks with DG have not been sufficiently studied. The article presents results of the flicker modeling in a network equipped with DG plants, implemented on the basis of synchronous generators. The results obtained indicated that with sharp disturbances caused by switching on and off an additional load, flicker is observed in networks with unregulated generators, accompanied by voltage and frequency fluctuations. Based on the wavelet transformation and spectral analysis methods, it was found that the power spectral density of the generated flicker-noise is inversely proportional to the frequency. The use of look-ahead control algorithms to control the excitation and rotors rotational speed of the DG plants generators, as well as concordant adjustment of their controllers, increases stability and removes flicker completely.