Voltage control of distribution networks with distributed generation

Effective voltage control is essential for the satisfactory operation of distribution networks. The increased connection of distributed generation to existing distribution networks challenges the current methods of controlling network voltages. Network voltage is primarily controlled by changing tap position of the primary transformers. The transformer secondary voltage will be automatically increased at times of high demand to compensate the voltage load drop. The experience of distribution network operators is that it can be difficult in practice to apply load drop compensation to primary substations with multiple feeders of disparate load profiles. The resultant compromise setting often results in a high network voltage, which may restrict the export from distributed generation connected to that substation. This paper presents an innovative solution to overcome this problem. In this method of voltage control, optimized compensation voltage is achieved using local current and voltage quantities based on feeder models. The effectiveness of the method is validated by comparison with traditional AVC control scheme. The results show that the new voltage control method allows an appropriate voltage level at substation that both complies with the statutory limits and leave more margins for connection of distributed generation.