Research And Development Of The System Of Deformation Of Power Transformer Windings

The power transformer is one of the important equipment in the electrical power system. Its safe running is of great importance for ensuring the security and reliability of electrical power system running. According to the statistics of the accidents, the accidents caused by the distortion of the transformer windings hold the very great proportion in the transformer total accidents. In order to promptly discover the transformer's hidden danger, avoid the accident's occurrence and enhance security and reliability of the transformer operation, it has the extremely vital significance to carry out the research of state inspection and fault diagnosis for deformation of power transformer windings.The Low Voltage pulse method (LVI), short-circuit resistance method (SCR) and frequency response analysis method (FRA), which can be used to measure and diagnose the deformation of power transformer windings, are introduced in the paper. By contrasting these three methods, the frequency response analysis is proposed for testing the winding distortion. The combination of frequency response analysis, frequency partition technology and the transfer function judgment method enhances the accuracy and the sensitivity of the examination of the winding distortion. Finally, based on the theory's research, an instrument which may test winding distortion on-the-spot was researched and designed.In the diagnosis system of deformation of power transformer windings, master controller adopts the dsPIC30F601 digital signal microcontroller containing DSP, which enhances the system's ability of data processing. This system can realize the production of scanning signal, high speed data acquisition and data storage, the communication with the superior computer and the man-machine exchange. In the third section of the paper, the design method of the system hardware is introduced in detail and each main function module has been designed. Content mainly include the signal generator module of producing scanning signal and clock signal for data acquisition, the module of data acquisition, storage and procession at high speed, USB communication module, the interface circuit of LCD monitor and keyboard, and so on.Diagnosis system software includes embedded system software and personal computer application program. The fourth part introduced the software design of embedded system. During of making program, we adopted the mixed procedure of assembler and C language, the main program uses the C language to program, and the essential algorithm realizes with the assembly language. In the article, each module design method is introduced in detail. Among them, the functions realized by embedded system software mainly include: the system initialization, the automatic updating of scanning signal and clock signal, the data acquisition and storage of exciting signal and response signal, the gathering signal filter and its spectral analysis as well as the firmware development of USB communication module, and so on.By using the basic principle of the frequency response method, testing system of transformer winding distortion can detect the degree and the position of distortion exactly after short circuit of transformer. This instrument can carry on the transformer winding distortion test and diagnosis effectively without lifting shield after the accident, so as to decrease the time of power cut and reduce the overhaul fee. The testing system has many social benefits and economical benefits.