500kV线路单相重合闸事故分析及对策

Accident Analysis and Coping Scheme of Single-phase Reclosing of 500 kV Power Line

在超高压电网中,为提高电网安全稳定性,通常采用单相重合闸方式。线路单相跳开后不存在系统非同期合闸问题,传统单相重合闸逻辑及其实现方式简单。2011年1月2日东北电网500kV伊换1号线发生永久性故障,线路单相重合闸失败,短路电流未能成功开断,造成断路器本体损坏,失灵保护动作跳开母线,扩大了电网事故。为规避同类事故的再次发生,深入分析了网络模型特征及其故障机理,提出了反映线路故障的短路电流特征因子,并界定了短路电流特征因子的门槛值,进而可识别出电网中重合闸存在的问题。最后,研究了当电网结构满足该特征时,应采取的电网重合闸方案。通过在实际电网中的运行检验,验证了该重合闸方案的有效性。

In order to improve the security and stability of power grid,a single-phase reclosing mode is usually adopted in the extra-high voltage(EHV) power system.As there is no non-simultaneous problem after a single-phase of the power line trip-out,the traditional single-phase reclosing logic and its realization method is simple.On January 2,201 1,a permanent fault of 500 kV Yihuan line 1 occurred in the Northeast Power Grid.The single-phase reclosing failed,and the short circuit current failed to break,resulting in breaker body damage.Then the failure protection acted and the bus jumped,expanding the power grid accident.In order to avoid similar accident to happen again,the network model characteristics and fault mechanism are analyzed in depth.A short-circuit current characteristic factor for reflecting the line fault is proposed.The threshold of the short-circuit current characteristic factor is defined,which can identify the existing problems of reclosure in the power network. Finally,the reclosure schemes that should be adopted are studied when the grid structure satisfies the characteristics.The effectiveness of the schemes is verified by the operation test in the actual power grid.