Dynamic ramp rate control for voltage regulation in distribution systems with high penetration photovoltaic power generations

Multiple voltage regulating devices, such as on-load tap changer (OLTC), step voltage regulators (SVRs), switching capacitors banks work in tandem with each other to regulate voltage in the distribution network. These conventional devices are based on volt/var optimization strategies that work in a time coordinated method. However, in case of distribution systems with Photovoltaic (PV) generations, a dynamically responsive voltage regulating device is required. Case studies are performed investigating voltage regulation at the PV bus during ramp up/down case. An alternate method using an energy storage device to regulate the target PV bus voltage during ramp up/down of PV power is proposed. A novel ramp rate control algorithm based on the current state of charge is also discussed. A benchmark MV distribution network model is developed and simulated in PSCAD/EMTD environment and the results validate the proposed coordinated voltage control strategy.