应对调相机励端击穿的转子电流保护

Improved Field Current Protection against Breakdown of Excitation Terminal for Synchronous Condenser

同步调相机励磁系统需要具备能够提供2.5倍励磁电流及3.5倍励磁电压的强励能力,过高的励磁电压存在击穿调相机励端正负极,导致励磁电流快速增大数倍的风险。本文结合某调相机强励试验中励端正负极击穿时的录波波形,分析了调相机励端正负极击穿时励磁系统的动作情况;通过分析发现此种情况下现有的励磁限制、转子保护存在局限性,由此提出了一种借助顶值励磁电流和最大可能励磁电流理论值及时发现励端击穿的转子电流保护,通过计算验证了提出的转子电流保护能够在励端正负极击穿情况下及时准确动作。

The excitation system of synchronous condenser is required to be capable of providing 2.5 times of field current and 3.5 times of field voltage.The high field voltage can cause breakdown of excitation terminal for synchronous condenser,resulting in the rapid increase of field current by several times.In this paper,the waveform of field voltage and field current during a synchronous condenser’s forced excitation test causing excitation terminal breakdown is given,by analyzing the waveform,it can be concluded that the existing excitation limit and rotor protection can’t handle this fault.So an improved field current protection which can find the breakdown of excitation terminal in time using the maximum field current and the maximum possible field current theoretical value is provided,and the improved method is verified by calculation.