发电机定子单相接地故障下定子铁芯的电弧烧损过程  

Arc burning process of stator core under stator single-phase grounding fault of generator

作　　者：龚衡 桂林[1] 周光厚 杨勇 王祥珩[1] GONG Heng;GUI Lin;ZHOU Guanghou;YANG Yong;WANG Xiangheng(State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment,Department of Electrical Engineering,Tsinghua University,Beijing 100084,China;Dongfang Electrical Machinery Company Limited,Deyang 618000,China)

机构地区：[1]清华大学电机系电力系统及发电设备控制和仿真国家重点实验室,北京100084 [2]东方电气集团东方电机有限公司,四川德阳618000

出　　处：《电力自动化设备》2022年第12期197-203,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(52077115)。

摘　　要：针对发电机定子单相接地故障导致定子铁芯烧损的问题,提出了基于电弧模型和定子铁芯温度场模型的仿真分析方法。首先,根据单相接地等值电路构建电弧模型,分析电路参数对电弧电压和电弧功率的影响。其次,建立定子铁芯温度场模型,利用有限元法计算电弧功率、故障时间等参数不同时铁芯的烧熔体积。仿真结果表明,电弧功率与接地故障电流大小、铁芯烧熔体积与电弧功率呈近似线性关系。最后,分析定子铁芯燃弧烧损试验数据,提出电弧功率模型,修正温度场模型,明确铁芯烧熔体积与接地故障电流大小的关系,并通过仿真与试验对比验证仿真分析方法的有效性。结合电弧烧损铁芯的仿真和试验以及电机制造厂家的铁芯局部修复水平,可以确定大型发电机的接地故障电流允许值最大为25 A。Aiming at the phenomenon of arc burning stator core under stator single-phase grounding fault,a simulation analysis method based on arc model and stator core temperature field model is proposed.Firstly,the arc model is built according to the single-phase grounding equivalent circuit,and the influence of circuit parameters on arc voltage and arc power is analyzed.Secondly,the temperature field model of the stator core is established,and the core melting volume of the core with different parameters such as arc power and fault time is calculated by finite element method.The simulative results show that the relationship between arc power and grounding fault current is approximately linear,so as the relationship between core melting volume and arc power.Finally,the arc power model is proposed by analyzing the data of stator core arc burning test,and the temperature field model is modified.The relationship between core melting volume and grounding fault current is clarified.The effectiveness of the simulation analysis method is verified by comparing with the test.Combined with the simulation and test results and the core repair level of the motor manufacturer,it can be determined that the maximum permissible value of grounding fault current of large generator is 25 A.

关 键 词：大型发电机 定子接地故障 定子铁芯烧损过程 电弧功率 铁芯烧熔体积 

分 类 号：TM307[电气工程—电机]