大型汽轮发电机转子匝间短路故障分析与诊断

发布时间：2018-04-02 00:26

本文选题：转子匝间短路　切入点：场路耦合　出处：《华北电力大学》2017年硕士论文

【摘要】：转子匝间短路故障是汽轮发电机常见故障之一,早期的准确检测对电力系统的安全稳定运行具有重要意义。发生转子匝间短路后,转子绕组有效匝数减少,磁动势相对减小且波形发生畸变,导致气隙磁场的畸变,从而发电机运行参数发生变化。为满足供电要求,发电机励磁系统的自动调节作用,励磁电流发生变化,各种故障特征量也会随之发生变化,影响故障监测和诊断的准确性,所使用检测方法的自身缺陷也会对故障监测与诊断造成一定影响。因此,各故障特征量变化的准确分析和新检测方法的提出,有利于提高转子匝间短路故障监测与诊断的准确性,对发电机的正常运行具有重大意义。本文主要工作如下:(1)以QFSN300-2型汽轮发电机为研究对象,利用Ansoft-Maxwell、Ansoft-Simplorer和Matlab-Simulink多软件联合,建立了基于场路耦合的汽轮发电机的仿真模型,并验证了模型的正确性。(2)分析了不同励磁模式下转子匝间短路时各故障特征量的变化规律。以恒励磁电流和恒励磁电压两种典型励磁模式为例,从磁场、基本电气量及电磁转矩的角度,分别计算和分析了联网下转子绕组匝间短路故障的基本特征,为自动励磁调节系统下发电机发生转子匝间短路奠定了研究基础。(3)提出了一种新型检测线圈法:U型检测线圈法。利用所建300MW汽轮发电机的仿真模型,且在发电机的定子铁芯处安装U型检测线圈。在空载和额定负载工况下,分别进行不同程度的转子匝间短路故障仿真,得到了流过U型检测线圈的磁通量和其感应电压的变化规律,从中发现,此种检测线圈法实用性较高,可作为转子匝间短路故障的诊断方法。
[Abstract]:Rotor inter-turn short circuit fault is one of the common faults of turbogenerator. Early accurate detection is of great significance to the safe and stable operation of power system.After the short circuit between turns of the rotor, the effective number of turns in the rotor winding is reduced, the magnetic EMF is relatively reduced and the waveform is distorted, which leads to the distortion of the air gap magnetic field, and the operation parameters of the generator change.In order to meet the demand of power supply, the automatic regulation of generator excitation system, the change of excitation current, and the variation of various fault characteristics will affect the accuracy of fault monitoring and diagnosis.The defects of the detection method can also affect the fault detection and diagnosis.Therefore, the accurate analysis of the variation of each fault characteristic quantity and the new detection method are helpful to improve the accuracy of rotor inter-turn short circuit fault monitoring and diagnosis, and are of great significance to the normal operation of the generator.The main work of this paper is as follows: (1) taking QFSN300-2 turbogenerator as the research object, the simulation model of turbogenerator based on field coupling is established by using Ansoft-Maxwell Ansoft-Simplorer and Matlab-Simulink software.The correctness of the model is verified. (2) the variation law of each fault characteristic quantity in rotor inter-turn short circuit under different excitation modes is analyzed.Taking two typical excitation modes of constant excitation current and constant excitation voltage as examples, the basic characteristics of inter-turn short circuit fault of rotor windings under interconnection are calculated and analyzed from the angles of magnetic field, basic electrical quantity and electromagnetic torque, respectively.In this paper, a new detection coil method is proposed, which lays a foundation for the research of rotor inter-turn short circuit of generator under automatic excitation regulation system.Using the simulation model of the 300MW turbogenerator, the U type detection coil is installed at the stator core of the generator.Under no-load and rated load conditions, different degree of rotor inter-turn short circuit fault simulation is carried out, and the variation law of magnetic flux and inductive voltage through U-shaped detection coil is obtained. It is found that the detection coil method is more practical.It can be used as a diagnosis method of rotor inter-turn short circuit fault.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM311

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