Coordinated voltage and reactive power control in the presence of distributed generation

This paper presents voltage and reactive power control methods in distribution systems in the presence of distributed generation (DG). Both uncoordinated and coordinated voltage control, without and with DG involved in the voltage control, are investigated. The uncoordinated voltage control means that all voltage and reactive power control equipment operate locally. The coordinated voltage control means that, in addition to the local operation, the voltage and reactive power control equipment will be adjusted remotely, based on wide area coordination, in order to obtain an optimum voltage profile and reactive power flow for a one-day-ahead load forecast and DG output planning. The result indicates that involving DG in the voltage control will result in a reduction of the losses, the number of OLTC operations and the reduction of the voltage fluctuation in the distribution system. Further, the results also indicate that the coordinated voltage and reactive power control, the losses can be decreased more.