College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China
This work is supported by National Key R&D Program of China (No. 2017YFB0903000) and National Natural Science Foundation of China (No. 51377162).
The unbalanced connection of large-scale residential photovoltaic (PV) power integrated into low-voltage distribution network (LVDN) will bring problems such as voltage violations, power losses and three-phase imbalance. In order to solve the problem that the accommodation control technology is not suitable to the three-phase four-wire low-voltage distribution system, a coordinated control method considering PV and energy storage system (ESS) is proposed based on three-phase four-wire optimal power flow (OPF). The network topology of LVDN is established by using three-phase four-wire node admittance, where the amplitudes and phase angles of voltage and current are considered. Multi-period coordinated control model of three-phase four-wire lines for active power of energy storage elements and reactive power of PV inverters is developed by overall considering the minimum of both power loss and three-phase imbalance. The difficulty of solving three-phase four-wire model is reduced through complex variable decomposition and model convexity, and the global optimal solution can be got by CPLEX method package. Simulation results show that the proposed OPF based control method can effectively mitigate the voltage violation in conditions of large-scale PV and load unbalanced connection, meanwhile the network power loss is reduced and the degree of three-phase imbalance is also optimized.
TANG Wei,LI Tianrui,ZHANG Lu,et al.Coordinated Control of Photovoltaic and Energy Storage System in Low-voltage Distribution Networks Based on Three-phase Four-wire Optimal Power Flow[J/OL].Automation of Electric Power Systems,http://doi.org/10.7500/AEPS20190609004.