计及不可预知型短路电流超标现象的复杂电网最优限流与保护类补救策略研究

In recent years, phenomena of interrupting capacity of circuit breaker due to excessive short-circuit current are reported frequently in more than one regional power grid. Meanwhile, a variety of new types of current limiting devices are being put into operation in the grid. The countermeasures on excessive short-circuit current need to be studied further. On the basis of the existing empirical short-circuit current limiting schemes, it is now necessary to further study the impact of the new fault current limiting technologies on the protection, the optimal current-limiting scheme, the on-line identification and strategy of the unpredictable excessive short-circuit current caused by significant changes in the grid operation mode, as well as the protection-based solution when all the measures above fail to work. This project focuses on improving the grid short-circuit current suppression capability, as well as providing systematic solutions on the problem of the excessive short-circuit current through circuit breaker. The research contents include: the impact of the new types of fault current limiting technology on the protection and its countermeasures, the system-level current-limiting optimization scheme sets and its cost evaluation, the identification of the endangered circuit breaker and the on-line formulation of its optimal current-limiting scheme, the substation-area integrated protection and the reclosing strategies in respond to the unpredictable excessive short-circuit current, and the test verifications of all the key technologies of solving the problem of excessive short-circuit current. The outputs of this project will theoretically provide a comprehensive system in governance over the excessive short-circuit current, pushing domestic research in this field to the international forefront.

近年来我国多个区域电网频繁出现的短路电流超标现象，以及各种新型限流设备即将投入电网运行的趋势，对电网短路电流超标治理策略提出新的要求：在现有经验型短路电流限制方案的基础上，还须对新的故障限流技术导入对保护的影响、最优限流方案的生成、因电网运行方式显著变化导致的不可预知型短路电流超标断路器在线辨识及应对策略，以及前述措施全部失效时保护级补救方案等问题进行研究。本课题以全面提升电网短路电流抑制能力和提出断路器短路电流超标问题系统性解决方案为着眼点，研究内容包括：新型故障限流技术对保护动作行为的影响及对策、系统级限流优化组合方案集生成及其代价评估、濒危断路器筛选及其限流最优方案在线制定、应对不可预知型短路电流超标的站域集成保护及重合闸策略、应对短路电流超标各项关键技术的测试验证等。本课题的研究成果将从理论上建立短路电流超标治理的完整体系，使我国在该领域研究走在国际前列。

本项目针对复杂电网不可预知型短路电流超标问题，提出了一系列的系统性应对策略和解决方案。首先基于实际电网真实数据建立了对应不可预知型短路电流超标问题的仿真模型，分析了不确定性短路电流超标现象产生的机理；针对新型故障限流器TCSC-FCL与SFCL的暂态特性，分析了其对保护带来的不利影响因素，提出了适应TCSC-FCL的基于动态偏移阻抗圆的距离保护整定方法，以及不受SFCL型限流器失超特性影响的和阻抗保护判据；研究了基于不同系统级与设备级限流措施组合的可行限流方案生成方法，提出了一种基于有限SFCL全局协同、计及SFCL寿命损耗的全生命周期限流方案成本校核与优化策略，实现了限流方案的经济性最优；提出了基于改进最小二乘法的不确定性超标短路电流快速预测策略与基于动态权重修正D-S证据理论的多判据融合策略，并在此基础上实现基于信息高度共享的站域集成保护架构的主动响应型站域集成保护策略；针对ARSIP造成的多线路开断的场景，提出了一种基于功率平衡的多线路重合闸策略；实现了包括短路电流预测、站域集成跳闸策略以及站域集成重合闸策略在内的全过程闭环仿真，完成了站域集成保护装置的样机开发，并完成了短路电流超标的典型场景下的RTDS测试工作，试验结果验证了本项目所提出的一系列短路电流超标应对策略的可行性和优越性。项目取得的主要知识产权成果如下：①研制了站域集成保护样机，可以适用于35kV以上电压等级的变电站，可在15ms内闭锁短路电流超标的故障线路跳闸，并在200ms内出口跳开优选的其它开关，在500ms内进行最优重合；②申请发明专利4项，实用新型专利2项；③在国内外期刊上公开发表论文30篇；④培养博士生4名，硕士生8名。本项目以加强电网运行安全性、全面提升电网短路电流抑制能力和断路器短路电流超标问题的补救性解决方案为着眼点开展研究，从多方面提出了解决复杂电网各种短路电流超标问题的基本理论和关键技术，为不可预知短路电流超标的辨识、预警和应对手段提供新的解决思路，也充实了继电保护的理论体系。