This article deals with the methods of finding partial discharge (PD) location in power transformers using ultra high frequency (UHF) measurements. The UHF technique utilises two methods to find the PD location, that is, the shortest path method and hyperbolic method. The shortest path method works based on the comparison of the measured data and the ones in the database. In the hyperbolic method, a hyperbolic equation is obtained between each two element subset of sensors. The coordinate that best fits all equations is known as the PD location, and can be obtained in three different ways, that is, iterative algorithms, the Fang method and Chan method. The convergence of iterative algorithms is limited by poor initial estimate, overshoot, mitigation of non-convergence etc. The Fang and Chan methods are two closed-form solutions that are used in the communication system to find the radiation source location. This article explains how to use these two methods to obtain the PD coordinate inside the power transformer. These two methods can find exactly the coordinate that best fits all hyperbolic equations. At the end of this article, several tests are carried out through CST software and the PD locations is estimated by all presented methods. The simulation results show how the Fang and Chan methods can overcome the limitations of the iterative method.

中文翻译：

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利用 UHF 技术在电力变压器中局部放电定位

本文介绍了使用超高频 （UHF） 测量查找电力变压器中局部放电 （PD） 位置的方法。UHF 技术利用两种方法来找到 PD 位置，即最短路径法和双曲法。最短路径法的工作原理是将测量数据与数据库中的数据进行比较。在双曲方法中，在传感器的每两个元件子集之间获得一个双曲方程。最适合所有方程的坐标称为 PD 位置，可以通过三种不同的方式获得，即迭代算法、Fang 法和 Chan 法。迭代算法的收敛受到初始估计不佳、超调、非收敛缓解等因素的限制。Fang 和 Chan 方法是通信系统中用于查找辐射源位置的两种闭式解决方案。本文介绍了如何使用这两种方法来获取电力变压器内部的 PD 坐标。这两种方法可以精确找到最适合所有双曲方程的坐标。在本文的最后，通过 CST 软件进行了几次测试，并通过所有提出的方法估计了 PD 位置。仿真结果显示了 Fang 和 Chan 方法如何克服迭代方法的局限性。