Substation demand reduction by CVR enabled intelligent PV inverter control functions in distribution systems

Summary This article proposes a combined scheme to reduce the substation demand with conservation voltage reduction (CVR) alongside intelligent photovoltaic (PV) inverter control functions. CVR maintains the power delivered to the customers in lower service voltage range (120‐114)V by not influencing electric devices' performance at the consumer premises. Since most of the loads are voltage‐dependent at the consumer side, proper voltage control can obtain substantial demand reduction and energy savings. In the proposed work, CVR is applied to both medium‐sized (IEEE‐123 node test feeder) and large‐sized (IEEE‐8500 node test feeder) unbalanced distribution feeders without PV and with intelligent PV inverter. In addition, the transient nature of PV output power is also examined during the movement of the clouds. The smart PV inverter utilizes various control functions (Volt‐VAr, Volt‐VAr [hysteresis], Volt‐Watt, and combi mode) to control the system's active and reactive power. Results reveal that operating CVR with intelligent PV inverter in the hysteresis Volt‐VAr mode helps achieve higher substation demand reduction than with only CVR operation. This combination reduces system losses and contributes to energy savings when better voltage regulation is provided. It also helps in maintaining the reliability and efficiency of the distribution network. In the proposed work, CVR is applied to an unbalanced three‐phase distribution feeder without PV and with intelligent PV inverter. The smart PV inverter utilizes various control functions (Volt‐VAr, Volt‐VAr [hysteresis], Volt‐Watt, and combi mode) to control the system's active and reactive power. Results reveal that operating CVR with intelligent PV inverter in the hysteresis Volt‐VAr mode helps achieve higher substation demand reduction than with only CVR operation.