电力变压器局部放电超高频检测仿真分析

Simulation analysis ofultra high frequency detection for partial discharge in power transformer

局部放电作为变压器的常见故障,若能及时发现处理并将其恢复到正常运行状态,将大大减少损失,提高供电可靠性。本文通过超高频检测法与时域有限差分法,分析了局部放电引起的超高频电磁波在变压器箱体中的传播特性,以及变压器箱体结构和铁芯绕组对电磁波信号的传播影响。在软件XFDTD上对局部放电辐射的电磁波在变压器内部的传播情况进行仿真,预测障碍物引起的PD信号到达时延,计算其与理论时延的差值,以此来评估对变压器PD定位精度的影响,并对其进行分析。仿真结果显示,从两个模型输出的数据结果中发现,在障碍物的存在下,引入的PD信号到达会出现估计微分时延。结论为变压器箱体对电磁波有衰减作用,所以传感器应放置于变压器内部;铁芯对电磁波也有畸变与衰减作用。

Partial discharge （PD）,as a common fault of transformer,can reduce the loss and improve the reliability of power supply if it can be found in time and restored to normal operation state. In this paper,the propagation characteristics of ultra high frequency（UHF） electromagnetic wave caused by partial discharge in transformer box and the influence of transformer box structure and iron core winding on the transmission of electromagnetic wave signal are analyzed by using UHF detection method and finite difference time domain （FDTD） method. On the software XFDTD,the electromagnetic wave of the partial discharge radiation is simulated in the transformer,and the PD signal arrival time delay caused by the obstacle is predicted,and the difference between the theoretical delay and the theoretical delay is calculated to evaluate the influence on the positioning accuracy of the transformer PD and to analyze it. The simulation results show that the estimation of differential delay is achieved when the PD signal introduced in the presence of obstacles exists in the data output from the two models. Conclusion the transformer box has attenuation effect on the electromagnetic wave,so the sensor should be placed inside the transformer,and the core also has distortion and attenuation effect on the electromagnetic wave. The simulation results show that from the data results of the two models,it is found that the estimated differential delay occurs when the introduced PD signal arrives in the presence of obstacles. The conclusion is that the transformer box has a damping effect on the electromagnetic wave,so the sensor should be placed inside the transformer,the iron core also has distortion and attenuation effect on the electromagnetic wave.