CVR-Based Real-Time Power Fluctuation Smoothing Control for Distribution Systems With High Penetration of PV and Experimental Demonstration

This paper proposes a real-time power smoothing control strategy for distribution systems with high penetration of photovoltaic (PV) based on conservation voltage reduction (CVR) technology, which employs CVR effects of feeder loads to smooth net-load power fluctuations caused by PV intermittency. CVR technology is implemented in real-time based on feedback signals provided by phasor measurement unit, and feeder voltage is under closed-loop control within statutory limits to make load demand change with PV power. Meanwhile, an online CVR model identification application based on generalized recursive least squares and a power smoothing application based on PI-Smith controller are separately designed. CVR model identification application uses well-designed M-sequence voltage disturbance to online induce CVR effects, which can accurately identify dynamic and steady-state CVR effects without being affected by color-noises. Power smoothing application combines PI controller with Smith predictor to limit the fluctuation rate of net-load without being affected by practical time-delay. The parameters of controller are automatically tuned through the identified CVR model with small computational burden, which is beneficial to engineering applications. The proposed method has been demonstrated in real 10kV distribution system in China. Simulation and field results demonstrate that proposed method has significant potential for real-time power smoothing.