电力建设2025，Vol.46Issue(8)：34-44,11.DOI:10.12204/j.issn.1000-7229.2025.08.004
面向不平衡电网的改进型电压支撑方法研究
Improved Voltage Support Method for Unbalanced Grid Condition
摘要
Abstract
[Objective]With the integration of large-scale distributed photovoltaics,issues such as reverse power flow and overvoltage arise,posing challenges to the safe and stable operation of power systems.To address this issue,both domestically and internationally,regulations mandate that PV systems must have grid support capabilities,such as voltage-reactive control,which actively regulates reactive power based on voltage deviations.However,such regulations are typically designed for balanced voltage scenarios and unbalanced voltage conditions are rarely considered.[Methods]Therefore,using voltage-reactive power control(volt-var control,VVC)as an example,this study analyzes the influence of voltage imbalance on the reactive power output and proposes an improved voltage-support control method aimed at minimizing three-phase voltage deviation.Based on instantaneous power theory,the mathematical relationship between voltage imbalance and active/reactive power is derived,demonstrating the voltage regulation effect of reactive power and the existence of the minimum voltage point.Then,with the three-phase voltage deviation as an index,the positive sequence voltage and reactive power corresponding to such point are calculated,and dynamic adjustments to the voltage-support control curve are made using this point,voltage limits,and reactive power capacity of PV inverters.[Results]Matlab/Simulink simulation results demonstrate that the proposed improved voltage-support control method ensures that three-phase voltages remain within limits while achieving minimal deviation from the nominal voltage under the lowest reactive power output.This ensures economical and efficient regulation of the three-phase voltage in unbalanced scenarios.[Conclusions]The proposed control strategy effectively coordinates the traditional VVC control with negative-sequence current/power control.It maintains three-phase voltages within grid-connected standard limits despite changes in irradiance,temperature,or other factors causing photovoltaic power fluctuations or voltage-unbalance variations,significantly enhancing the adaptability of conventional VVC control functions.关键词
不平衡电网电压/光伏并网变换器/电压支撑/功率控制/瞬时功率理论Key words
unbalanced grid voltage/grid integration of PV/voltage support/voltage-reactive power control/instantaneous power theory分类
信息技术与安全科学引用本文复制引用
曹晓庆,李特,李林,陈迪,周正旭,时晓洁..面向不平衡电网的改进型电压支撑方法研究[J].电力建设,2025,46(8):34-44,11.基金项目
国家自然科学基金青年科学基金项目(52307202) This work is supported by the National Natural Science Foundation of China(No.52307202). （52307202）
