Voltage-Sensitivity-Based Volt-VAR-Watt Settings of Smart Inverters for Mitigating Voltage Rise in Distribution Systems

Active and reactive power control using smart inverters (SI) is highly effective in mitigating voltage rise in distribution systems, which is caused by the high penetration of photovoltaic (PV) power generation. However, the voltage control performance depends on the SI settings. We propose a new approach that uniquely determines the parameter settings for volt-VAR-watt control based on the active and reactive power-voltage sensitivity matrix of SIs. Because the voltage sensitivity matrix is calculated based solely on the impedance of the distribution system and it does not vary with time or the number of SIs, the proposed method can determine the individual SI parameter settings theoretically and efficiently without the need for optimization problem formulation, power flow calculation, or communication between the SIs. To evaluate the proposed method, the voltage control performance in a real distribution system model with a large number of PV installations is compared with that of volt-VAR-watt control using default parameters and optimized parameters in case that the load demand and PV generation are given in advance. The results show that the proposed method achieves better control performance than other conventional methods in terms of all the evaluation indices; in particular, it realizes effective control in the case of voltage rise. Furthermore, the proposed method can also achieve the same level of voltage control performance as the optimization results, even though it uses only the voltage sensitivity matrix and SI rating capacities for parameters determination, and the accuracy of the proposed voltage control can be ensured.