基于有限差分法的变压器局部放电高频信号的传播特性研究

Research of Propagation Characteristics of High-frequency Partial Discharge in Transformer Based on FDTD

基于高频的局部放电检测技术有着具有检测灵敏,结构简单,技术成熟的特点。但目前对这项技术的研究还停留在实际应用上,而对其在变压器中传播理论研究并不多。为此文中基于有限差分法(FDTD),在对一个35 kV变压器建模基础上,对比研究了放电源脉冲宽度,幅值,接收源距离以及铁心对高频局部放电信号的影响,并设计—气隙型局部放电,在真型变压器上完成了高频局部放电检测试,验证完整了仿真结论。仿真与试验结论表明高频局部放电信号在传播特性上,受到多种因素的影响,与特高频信号有明显区别。研究结果有助于对局部放电的理解,也对高频局部放电的测量定位在理论上提供了依据,从而在工程中起到指导作用。

High-frequency(HF) partial discharge(PD) detection technique has high sensitivity, simple structure, mature technology and so on. It researches mainly on the practical application, but there is little research on transformer signal propagation theory. In this paper, basing on finite difference time domain(FDTD) method, a computer model of a 35kV transformer is built up, and the impact of the pulse width, amplitude, distance of the source and the transformer core on HF PD is compared. Moreover, a HF PD test is performed on a real transformer to verify the integrity of the simulation results. Simulation and experimental results show that the propagation characteristics of HF PD signals subjects to a variety of factors, and it is significantly different from UHF signals. The research is helpful to the understanding of PD, and also provides a theoretical basis for the measurement and location of HF PD, which could play a guiding role in the practical application.