Voltage Variation Sensitivity Analysis for Unbalanced Distribution Networks Due to Photovoltaic Power Fluctuations

In a geographically small distribution area, fast moving clouds may cover the whole area within a short period causing photovoltaic (PV) power to drop. When a feeder loses PV power support, bus voltages will decrease. In an unbalanced network, asymmetrical spacing and non-transposition of line configurations can result in different voltage drops for each phase. This may potentially cause some voltage problems after a decline in PV generation, such as an extremely low voltage magnitude of a certain phase and an unacceptable voltage imbalance level at a remote bus. This paper proposes a method of analyzing voltage variation sensitivity due to PV power fluctuations in an unbalanced network (unbalanced line configuration and phase loading levels). Based on this method, a network reconfiguration solution is developed to solve the voltage problems. This solution utilizes unbalanced line characteristics and realizes the potential of the network, so no extra compensation devices are needed for network support.