Overvoltage Mitigation through Volt-VAR Control of Distributed PV Systems

The increasing penetration of distributed PV systems challenges the distribution system voltage profile. When the system loading level is relatively low on a sunny day, the reverse power flow is expected to be large and the bus voltage is likely to exceed the upper bound. This paper conducts a sensitivity study on the Volt- VArcontrol of distributed PV systems for mitigating the overvoltage problem. The distribution system components, including the ZIP load, shunt capacitor and onload tap changer, are fully considered. The simulation study indicates that the Volt-VArcontrol can effectively reduce the daily maximum bus voltage and slightly reduce the network power loss. In addition, this control scheme does not require additional VAR compensation and communication devices. Therefore, it has great potential in future distribution systems if the PV penetration keeps increasing.