Considering urban substations ground grid diagnosis, some real-physical constraints result in measurement process challenges: 1) limited length between electrodes used to measure the equivalent impedance of the grounding system; 2) to determine the current that flows from ground grid conductors to the earth; and 3) to determine the grid resistance. In this scenario, an adequate diagnosis of the safety offered by the ground grid under test when a ground fault occurs is not a trivial task. This article describes a methodology that allows a reliable diagnosis regarding the safety provided by a substation ground grid. The methodology is applied to the parameters obtained in performed field tests. The method has two steps. First, the fall-of-potential method with reduced distances between electrodes is used to determine the equivalent impedance of the grounding system. Then, the ground current is obtained. In both stages, optimization techniques are applied to the specific equations that govern the phenomenon under investigation. Comparative case studies considering real-life data illustrate the effectiveness of the method.

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应用基于测量和现场测试的优化技术的变电站接地网诊断

考虑到城市变电站接地网诊断，一些实际物理约束导致测量过程挑战：1）用于测量接地系统等效阻抗的电极之间的长度有限；2）确定从地网导体流向大地的电流；3) 确定栅极电阻。在这种情况下，当发生接地故障时，对被测接地网提供的安全性进行充分诊断并非易事。本文介绍了一种方法，可对变电站接地网提供的安全性进行可靠诊断。该方法应用于在执行的现场测试中获得的参数。该方法有两个步骤。第一的，使用减小电极间距离的电位降法来确定接地系统的等效阻抗。然后，获得接地电流。在这两个阶段，优化技术都应用于控制所研究现象的特定方程。考虑现实生活数据的比较案例研究说明了该方法的有效性。