A study of PD location issues in GIS using FDTD simulation
A study of PD location issues in GIS using FDTD simulation
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发表时间：
2010-12
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通讯作者：
X. Hu;M. Judd;W. H. Siew
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作者：
X. Hu;M. Judd;W. H. Siew
超高频法是测量GIS局部放电的一种有效方法，可以实现局部放电的检测和定位。局部放电定位是基于时间-光计算，其中两个传感器之间的电磁信号的传播路径被假定为轴向沿着GIS的中心。因此，通常通过解决一维问题来获得位置，就好像GIS在连续的直线上一样。但是，通常GIS必须非常紧凑，这可能需要许多直角弯头或T形截面。拐角和T形截面的作用是对PD位置空间的三维特征给予更大的意义。特别地，当传感器靠近T形部分定位时，取决于其安装在罐圆周上的位置，定位结果可能变化，因为其不考虑该传感器与T形部分的不同臂中的另一传感器之间的三维关系。采用时域有限差分法（FDTD）模拟局部放电辐射电磁信号的传播，研究了GIS T形截面中局部放电的定位精度。定义了GIS的T形截面模型，并利用在SF6中测量的局部放电电流脉冲来量化激励源的波形。进行了模拟，并在可能安装在T形部分周围的UHF传感器的各个点处监测电场。通过飞行时间计算对局部放电进行了定位，并对定位误差进行了分析。通过这些手段，潜在的不准确性，在GIS中的局部放电定位进行了调查和量化。最后得出结论，超高频传感器的定位，以减少定位误差。
An effective way of measuring partial discharge (PD) for GIS is the UHF method, by which both PD detection and location can be realized. PD location is based on time-off-light calculation in which travelling paths of electromagnetic signals between two sensors are assumed to be axially along the centre of GIS. The location is therefore normally obtained by solving a one dimensional problem, as if the GIS was in a continuous straight line. However, usually GIS must be made very compact, which can require many right angle bends or tee sections. The effect of corners and tee sections is to give greater significance to the three dimensional character of the PD location space. In particular, when a sensor is located close to a tee section, depending on where it is mounted on the tank circumference, the location result may vary because it does not consider the three dimensional relationship between this sensor and another sensor in a different arm of the tee section. This paper describes an investigation into the PD location accuracy in GIS tee sections using the Finite Difference Time Domain (FDTD) method to simulate the propagation of electromagnetic signals radiated by a PD. A tee section model of GIS was defined and a PD current pulse measured in SF6 was used to quantify the waveshape of the excitation source. Simulations were carried out and electric fields were monitored at various points where UHF sensors might be installed around the tee section. PD location was evaluated by time-of-flight calculation and the location errors were analyzed. By these means, potential inaccuracies of PD location in GIS were investigated and quantified. Conclusions were drawn regarding the positioning of UHF sensors to reduce the location error.