Research Signal Waveform Selection On Online Detection Fault Of Transformer Winding

Transformer is one of the most important electrical equipment in power system. It has great significance to keep its safety operation for ensuring the whole safe operation of the power grid. The winding deformation is one of the common types of transformer faults, the winding deformed seriously will damage the transformer, resulting in a large area blackout and bring great losses to the national economy.In response to the deformation of power transformer windings, domestic and foreign scholars have done a lot of research work. As online application of the frequency response method,online injecting signal is considered to be a method which can implement online fault detection of winding, but related research about the real and effective application of this method is rarely reported. Many online injection signal method can not be used in online detection lies in choosing injected signal not based on the actual situation of the scene. Therefore, carrying out researching on selection injected signal waveform of online winding fault detection,which can make up for the inadequacy of online injection signal method. In this paper, the main research work is as follows:①Aiming at the shortcomings of the winding fault detection method which is based on online signal injection, introducing a kind of winding fault online detection method based on coupling of the injected signal.in order to make the method be applied to online and achieve the normal operation of hanging in the power grid, this paper analysis of the various types of excitation source used in fault detection of winding from the theoretical,and select a injected signal which can inject the winding online, nondestructive, active, and effectively obtain winding frequency response.Then the choice of parameters of the injected signal are analyzed theoretically.②In order to guide the development of the injected signal generator and winding detection device,this paper analyze the type and parameter of the injected signal through the simulation of a variety of winding fault states based on the winding high frequency equivalent model, and validated by simulation, get a lot of useful conclusions to provide the basis for the subsequent development of device.③By the theory analysis and simulation results, developing the signal generator and related equipment for winding online fault detection in laboratory, and using the developed equipment analyze the typical fault winding transformer, health transformer and fault transformer respectively under off-line situation, and finally into the online application of signal detection of 750 k V high voltage parallel reactor winding faults using the sigal with typical parameter, the equipment in operation condition, obtains the time domain signal of high signal-to-noise ratio,thus constructing frequency response curve to the in-depth analysis of winding fault.