变压器绕组变形在线检测技术研究

发布时间：2018-06-23 02:25

本文选题：变压器 + 绕组变形　；参考：《华北电力大学(北京)》2017年硕士论文

【摘要】：变压器是电力传输中的核心设备之一。变压器绕组变形故障是变压器的常见故障之一,特别是在发生短路后,要及时对绕组进行诊断,判断是否变形。人类的生产生活都要求保证电力的持续供应,减少停电次数。对于绕组变形检测,现场目前都是在变压器离线条件下进行的,本文追求的目标是实现带电检测。绕组发生变形后,绕组等效网络传递函数的零点、极点会发生变化,进而引起幅频响应的改变。频率响应法是目前离线检测变压器绕组变形缺陷的主要方法之一,将其应用于在线运行的变压器时,主要存在两个问题,一是需要解决如何向带电运行的变压器绕组注入激励信号和检测响应信号,另一个是如何消除与变压器绕组直接相连的外部设备的影响。本文针对有中性点引出的星形接法变压器,提出了通过磁场耦合的方法,利用罗氏线圈向绕组耦合注入扫频激励信号,同时利用罗氏线圈放在高压套管根部,测量电流响应信号;设计了所需要的罗氏线圈,进行了离线验证试验,试验表明磁场耦合的方式是可行性,解决了变压器在线运行时获得绕组幅频响应曲线的问题。在以电压信号为激励,电流信号为响应获得绕组等效网络的幅频响应函数后,理论分析和仿真研究了外部设备的影响和消除方法,得到绕组等效网络的传递函数的零点不受外部设备的影响,提出了将幅频响应曲线上零点对应的点是否变化作为绕组变形的判据,仿真结果验证了这种方法的正确性,并试验验证了零点不受外部设备的影响。
[Abstract]:Transformer is one of the core equipments in power transmission. Transformer winding deformation fault is one of the common faults of transformer, especially after the short circuit occurs, the winding should be diagnosed in time to judge whether it is deformed or not. The production and life of human are required to ensure the continuous supply of electricity and reduce the number of power outages. The detection of winding deformation is carried out under the condition of transformer off-line at present. The aim of this paper is to realize live detection. After the winding is deformed, the zero of the equivalent network transfer function and the pole will change, which will cause the change of the amplitude frequency response. Frequency response method is one of the main methods for detecting transformer winding deformation defects. There are two main problems in the application of frequency response method to the on-line operation of transformers. One is to solve the problem of how to inject excitation signals and detect response signals into transformer windings running live, and the other is to eliminate the influence of external equipments directly connected to transformer windings. In this paper, a magnetic field coupling method is proposed for star-connected transformers with neutral points, in which the Roche coil is used to inject the sweep frequency excitation signal into the winding coupling, and the Roche coil is placed at the root of the high voltage casing. The current response signal is measured, the Roche coil is designed and the off-line verification test is carried out. The experiment shows that the magnetic field coupling method is feasible and solves the problem of obtaining the winding amplitude-frequency response curve during the on-line operation of the transformer. After the amplitude-frequency response function of the equivalent winding network is obtained by using the voltage signal as the excitation and the current signal as the response, the influence of the external equipment and the elimination method are theoretically analyzed and simulated. It is obtained that the zero point of the transfer function of the equivalent winding network is not affected by the external equipment. Whether the zero point corresponding to the amplitude-frequency response curve is changed is taken as the criterion of winding deformation. The simulation results verify the correctness of this method. The experimental results show that the zero point is not affected by the external equipment.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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