【摘要】 为了解决电网电压不平衡导致同步发电机定子绕组匝间短路故障诊断存在误判问题，提出一种基于环流瞬时功率直流分量的故障诊断方法。首先，对气隙磁场进行分析，推导出同步发电机并联支路的环流特性，得到故障后环流瞬时功率的特征频率；其次，以QFSN-300-2-20B汽轮发电机为例建立同步发电机有限元仿真模型，分析了同步发电机在不同过渡电阻、不同故障匝数和电压不平衡条件下环流瞬时功率的变化规律；最后，通过实验室的故障模拟同步电机进行实验验证。结果表明，当同步发电机发生定子绕组匝间短路故障后，将会产生较高的环流瞬时功率，主要包含直流分量和偶次谐波，且环流瞬时功率直流分量对于诊断定子绕组小匝数轻微匝间短路故障具有较高的灵敏性，对电网电压不平衡具有较好的鲁棒性。更多还原

【Abstract】 To address the misjudgment issue in fault diagnosis of inter-turn short-circuit faults in synchronous generator stator windings caused by grid voltage unbalance, a fault diagnosis method based on the DC component of instantaneous circulating current power was proposed. Firstly, the air gap magnetic field of the synchronous generator was analyzed, the circulating current characteristics of the parallel branches were derived, and the characteristic frequency of the instantaneous circulating current power under fault conditions was obtained. Secondly, taking the QFSN-300-2-20B turbine generator as an example, a finite element simulation model of the synchronous generator was established to analyze the variation of the synchronous generator’s instantaneous circulating current power under different transition resistances, fault turn numbers, and grid voltage unbalance. Finally, the conclusions were experimentally validated. The results indicate that when a stator winding inter-turn short circuit fault occurs in a synchronous generator, a high instantaneous circulating current power will be generated, which primarily consists of a DC component and even harmonics. The DC component of the instantaneous circulating current power shows high sensitivity for diagnosing minor inter-turn short circuit faults in the stator winding and exhibits good robustness against grid voltage unbalance.更多还原