考虑电网不平衡影响的配电网故障仿真分析
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摘要
针对配电网因三相不平衡而导致的现有选线方法选线效果不理想的现状,分析了三相不平衡产生的原因,通过对对地电容不平衡、负荷不平衡以及电流互感器参数不对称引起的不平衡电流进行理论分析,论证系统三相不平衡下会产生零序电流,造成选线失败。为提取在电网不平衡下的单相故障特征信号,用MATLAB/Simulink软件搭建了三相不平衡谐振接地系统的配电网单相故障仿真模型,通过改变仿真模型的参数,模拟电网不平衡下电网单相接地故障。通过对不平衡配电网单相故障进行大量仿真实验,分析了现有选线方法在三相不平衡条件下选线效果,为研究电网不平衡条件下的单相故障选线方法提供理论依据。
At present,the grounding line selection effect of the small current system is not satisfactory because of the three-phase unbalance of distribution network. The causes of three-phase unbalance are analyzed. In addition,the causes of unbalanced current caused by unbalanced capacitance,unbalanced load and asymmetric parameters of current transformer are conducted through theoretical analysis. It is verified that the three-phase unbalance will generate the zero-sequence current,which leads to the failure of line selection theoretically. In order to extract the characteristic signal of single-phase fault in unbalanced power grid,a simulation model of single-phase fault in three-phase unbalanced resonant grounding system is built by using MATLAB/Simulink software. The effect of existing line selection methods under threephase unbalanced condition is analyzed through a large number of simulation experiments on unbalanced distribution network single-phase fault,which provides a theoretical basis for the study of single-phase fault line selection method under unbalanced conditions.
At present,the grounding line selection effect of the small current system is not satisfactory because of the three-phase unbalance of distribution network. The causes of three-phase unbalance are analyzed. In addition,the causes of unbalanced current caused by unbalanced capacitance,unbalanced load and asymmetric parameters of current transformer are conducted through theoretical analysis. It is verified that the three-phase unbalance will generate the zero-sequence current,which leads to the failure of line selection theoretically. In order to extract the characteristic signal of single-phase fault in unbalanced power grid,a simulation model of single-phase fault in three-phase unbalanced resonant grounding system is built by using MATLAB/Simulink software. The effect of existing line selection methods under threephase unbalanced condition is analyzed through a large number of simulation experiments on unbalanced distribution network single-phase fault,which provides a theoretical basis for the study of single-phase fault line selection method under unbalanced conditions.
引文
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[13]王建元,张峥.基于注入信号与小波能量的小电流接地故障选线研究[J].电测与仪表,2018,55(5):28-32.
[2]彭仕欣.谐振接地系统故障选线新方法研究[D].昆明理工大学,2008.
[3]林志雄,陈岩,蔡金锭,等.低压配电网三相不平衡运行的影响及治理措施[J].电力科学与技术学报,2009,24(3):63-67.
[4]王代弟.配电网三相不平衡问题的分析与研究[D].沈阳工业大学,2007.
[5]徐海亮,章玮,周鹏.电网电压不平衡及谐波畸变时基波电压同步信号的检测[J].电力系统自动化,2012,36(5):90-95.
[6]时劲松. IDC供电系统三相不平衡度控制策略研究[D].中国计量学院,2012.
[7]吴联梓,王磊,司远.浅谈配电网三相负荷不平衡问题[J].科技展望,2014,(23):81.
[8]刘奇.小电流接地系统选线装置的实用化研究[D].华北电力大学,2011.
[9]郭清滔,吴田.小电流接地系统故障选线方法综述[J].电力系统保护与控制,2010,38(2):146-152.
[10]侯玉强,高彦成,张晓.基于PSCAD的经消弧线圈接地系统仿真分析[J].煤矿机电,2011,(1):60-64.
[11]周浩,余宇红,张利庭,等.楼其民. 10kV配电网铁磁谐振消谐措施的仿真比较研究[J].电网技术,2005,(22):24-34.
[12]殷培峰,刘石红.基于谐波与首半波结合的单相接地选线分析与研究[J].自动化与仪器仪表,2013,(4):19-21,225.
[13]王建元,张峥.基于注入信号与小波能量的小电流接地故障选线研究[J].电测与仪表,2018,55(5):28-32.