发电机-变压器组过励磁保护若干问题的研究

Studies on the Problems of Generator-transformer Unit Over-excitation Protection

对大型发电机—变压器组过励磁保护的3个问题进行了分析,分别是:保护动作特性曲线与设备过励磁曲线的配合、保护算法的性能以及保护应用中的相关问题。针对前2个问题,通过对不同动作特性曲线、算法的性能对比分析结果表明,基于分段原理的动作特性曲线和基于反时限保护动作状态与动作量基本关系的算法具有更好的性能,由这两者构成的过励磁保护方案能对机组起到更有效的保护作用。对于第3个问题,通过对保护的电压、定值和动作出口方式进行合理的选取和设置,可以在保证机组安全的基础上,充分发挥机组的效益。

Three problems are analyzed for the large generator-transformer unit over-excitation protection, i.e. the matching between protection operating characteristic curve and equipment＇s over-excitation curve, the performance of protection algorithm and the related problems about protection application. For the first two problems, the performance of several operating characteristic curves and algorithms are compared and analyzed. The analysis results show that the segmental fitting operating characteristic curve and the algorithm based on the inverse time protection basic relation between operation state and action value have better performance, the protection scheme combining the operating characteristic curve and algorithm can protect generator-transformer unit more effectively. For the third problem, the voltage, setting points and operating modes of protection should be fine tuned, to achieve both high efficiency and safe operation for the generators.