摘要
发现交直流系统中三相重合时序对距离保护有较大影响。建立交直流并联系统模型,在交流输电线路发生对称性故障时,推导出不同三相重合时序下健全线路两端测量阻抗的表达式。据此,解析出影响距离保护动作特性的临界故障距离,并探究测量阻抗随整流、逆变侧系统电抗的变化规律。直流系统发生换相失败时推导出直流系统等效阻抗与故障电压变化量、越前触发角等电气量的关系式,根据该关系式分析健全线路测量阻抗随故障电压变化量和越前触发角的变化趋势,得出减小交直流并联系统健全线路距离保护误动风险的最佳重合时序方案。其正确性和有效性在两区域交直流并联系统中得到验证。
Significant effect of three-phase reclosure sequence on distance protection in AC-DC system has been discovered. AC and DC parallel system model is established, expression of measuring impedance on perfect line ’ s both sides is deduced under different reclosure sequences when AC transmission line symmetry fault occured. Hereby, the critical analysis of the impact of distance protection characteristics of fault distance, and to explore the measuring impedance with the rectifier and inverter system variation of the reactance. Commutation failure in DC system, the relationships among DC system’ s equivalent impedance with fault voltage component and fire angle are derived. According to the expression, analyzing on the variation trend of the perfect line’ s measured impedance along with the fire angle and fault voltage component, and obtain the best reclosure sequence method that decreases the risk of distance protectionJ s maloperation in DC parallel system. Simulation results of two-area AC-DC series system verify the conclusions ’ correctness and validity.
出处
《电工技术学报》
EI
CSCD
北大核心
2017年第1期32-39,共8页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(51367009
50847043)
关键词
三相重合时序
距离保护
交直流并联系统
误动
Three-phase reclosure sequence, distance protection, AC-DC parallel system, maloperation
