Coordinated Centralized Voltage Regulation Scheme for Bus Voltage Control Using Distributed PV Sources

Voltage deviation in power systems, particularly during overloading and light load conditions, has become a significant concern. To address this issue, Photovoltaic (PV) sources are used to compensate for voltage deviations within the specified range. Existing control schemes, such as P-Q-V droop and network agonist adaptive PQ method, are uncoordinated and can lead to overloading and stress on the system. To address this need, a centralized supervisory voltage controller (CSVC) is proposed in this paper to minimize voltage deviations at various buses. The CSVC uses a wide area measurement system (WAMS) to obtain information on bus voltage. Based on the available voltage deviations, the CSVC assigns reference active and reactive power signals to each local controller of the distributed PV source. By coordinating the power injection from multiple PV sources, the proposed CSVC ensures balanced and proportionate sharing of active and reactive power, thereby reducing stress on PV source converters. The main achievement of this paper is demonstrating that the proposed CSVC can regulate the voltage of the buses within the required limits during underload and overload conditions. The reference signals allocated by the proposed CSVC are designed so that each PV source supplies active and reactive power in proportion to its rated capacity. This helps reduce the overloading of PV source converters. The effectiveness of the proposed CSVC scheme is successfully validated on a real-time digital simulator (RTDS) platform, that maintains bus voltages within 0.95-1.05 pu, limit by coordinating three PV sources as compared to one and two PV source.