汽轮发电机转子绕组匝间短路故障恶化的影响因素研究

Research on the Factors Influencing the Deterioration of Inter-turn Short Circuit Fault in Turbo-generator Rotor Winding

转子绕组匝间短路是大型同步发电机的常见故障,在发电机的电气故障中占据了较高的比例,也是影响机组安全运行的主要原因之一。本文针对转子绕组匝间短路伴随的局部过热问题,分别研究了短路点过渡电阻、短路点电流集束效应以及短路点的反复通断过程对其的影响。以一台300MW汽轮发电机为例,仿真获取了短路回路电流和功率损耗、短路点附近励磁电流密度以及被短路回路的暂态电压规律。本研究为确定转子绕组匝间短路故障的过热现象原因奠定了理论基础,也为进一步研究故障演化过程提供了分析思路。

Inter-turn short circuit of rotor winding is a common fault in large generators,accounting for a high proportion of generator electrical faults,and also one of the main reasons affecting the safe operation of the units.This article focuses on the local overheating problem associated with inter-turn short circuits in rotor windings,and investigates the effects of short-circuit point transition resistance,short-circuit point current beaming effect,and the repeated conduction and disconnection process of short circuit points.Taking a 300MW turbine generator as an example,the short-circuit loop current and power loss,the excitation current density near the short-circuit point and the transient voltage law of the short-circuit loop are obtained by simulation.This study lays a theoretical foundation for determining the cause of overheating phenomenon of rotor winding inter-turn short circuit fault,and also provides an analytical approach for further study of fault evolution process.