500kV主变压器高压侧断路器失灵联跳主变压器三侧断路器优化

Optimization on Failure Protection of High-voltage Side Breaker of 500 kV Main Transformer Tripping on Breakers at Three Sides

在500 kV主变压器高、中压侧断路器同时失灵的情况下,现有失灵保护实现方式不能快速将故障从系统中隔离,对此提出2种失灵联跳主变压器三侧的方案,可以将故障从系统中隔离的时间压缩到故障后0.60~0.65 s。通过MATLAB/Simulink建立4种典型故障模型,分析500 kV主变压器高、中压侧断路器同时失灵时,断路器中故障电流及相对应的电压变化情况,得出结论:在原有的失灵保护实现方式下,对于不同类型故障,故障点被隔离的时间不同,最快在1.60 s被隔离,但也可能没有保护能将故障点从系统中隔离。仿真分析也验证了所提方案的可行性及有效性。

In case of simultaneous failure of the high-voltage side breaker and the medium-voltage side breaker of the 500 kV main transformer,current failure protection can not quickly isolate the fault from the system.Therefore,this paper proposes two schemes of breaker failure protection tripping on three sides of the main transformer,which can shorten fault isolation time within 0.60~0.65 s after the fault.By using MATLAB/Simulink software,it establishes four typical fault models to analyze fault currents and voltages in the breakers as the high-voltages side breaker and the medium-voltage side breaker of the 500 kV main transformer are in failure at the same time.Then it comes to conclusions that under the original failure protection implementation way,the isolation time of fault points is different with regard to different faults,and the fastest time is 1.60 s,but there may be no protection isolating the fault point from the system.The simulation analysis also verifies feasibility and validity of the proposed schemes.