摘要
双端直流配电网是一种双端电源供电的网络结构,可为直流负荷提供更加稳定和可靠的电源电压。然而,负荷的功率波动和不平衡使线路电压跌落增大,可能导致直流负荷的电压不平衡度和电压偏差指标越限,影响直流负荷的正常运行。文中基于电压源型换流器(VSC)外环电压控制,考虑中线电压补偿,提出基于电压补偿等效模型的直流配电网电压偏差及不平衡度联合抑制策略,实现直流配电网电压就地协调控制。首先,建立双端直流配电网潮流模型,将VSC电压下垂控制引入潮流模型,分析不同控制策略下的电压偏差和不平衡度的特性。其次,在此基础上,以电压最低点为分点获得双端电源供电回路压降的简化等效模型,并利用最小二乘法实现等效阻抗参数辨识,构建双端直流配电网的电压补偿等效模型。以参数辨识结果作为电压外环控制输入,提出考虑中线电压补偿的双端直流配电网电压就地协调控制策略。最后,在MATLAB/Simulink中搭建仿真模型,验证了双端直流配电网潮流模型的正确性和控制策略的有效性。
Two-terminal DC distribution networks are a type of network structure powered by two-terminal power sources,providing a more stable and reliable supply voltage for DC loads.However,power fluctuations and unbalanced loads increase the voltage drop on the line,which may lead to the voltage deviation and imbalance index of DC loads exceeding the limit,obstructing the normal operation of DC loads.Based on the outer-loop voltage control of the voltage source converter(VSC),and considering the neutral line voltage compensation,this paper proposes a joint suppression strategy for the voltage deviation and imbalance of DC distribution network based on the voltage compensation equivalent model,to realize the local coordinated voltage control of DC distribution network.First,the paper establishes a power flow model of the two-terminal DC distribution network,introduces the VSC voltage droop control into the model,and analyzes the characteristics of voltage deviation and imbalance under different control strategies.Then,on this basis,a simplified equivalent model of voltage drop in the two-terminal power supply circuit is obtained by taking the lowest voltage point as the dividing point,and the least square method is used to identify the equivalent impedance parameters,constructing the voltage compensation equivalent model of two-terminal DC distribution network.Taking the parameter identification results as the voltage outer-loop control input,a local coordinated voltage control strategy for twoterminal DC distribution networks considering the neutral line voltage compensation is proposed.Finally,a simulation model is built in the MATLAB/Simulink to verify the correctness of the power flow models of the two-terminal DC distribution network and the effectiveness of the control strategy.
作者
王强钢
宋佳航
廖建权
周念成
许晓龙
WANG Qianggang;SONG Jiahang;LIAO Jianquan;ZHOU Niancheng;XU Xiaolong(National Key Laboratory of Power Transmission Equipment Technology(Chongqing University),Chongqing 400044,China;College of Electric Engineering,Sichuan University,Chengdu 610065,China)
出处
《电力系统自动化》
EI
CSCD
北大核心
2024年第7期277-287,共11页
Automation of Electric Power Systems
基金
国家自然科学基金资助项目(52077017)。
关键词
直流配电网
中线电压补偿
下垂控制
最小二乘法
潮流模型
DC distribution network
neutral line voltage compensation
droop control
least square method
power flow model
