接地电阻测量与三维地网

许多发、变电站建在山区或者周边环境比较恶劣，所处位置的土壤电阻率比较大，即便是建在城市中的发、变电站也要受到占地面积的限制。因此如何在这些高土壤电阻率、扩张裕度有限的地区，使发、变电站地网满足设计规范标准，以确保人身及设备的安全，则是人们所关心的问题。首先需要准确测量接地电阻的大小，测量接地电阻的方法很多，通过分析接地电阻测量的基本原理，探讨理想接地球体状况下的三极直线法（0．618法）和三极三角形法（30°夹角法），对类似接地工程的设计、施工及测量具有一定的参考价值和借鉴作用。实践表明：增设垂直接地体，采用三维立体接地网（文中简称三维地网）新技术，对于降低接地网接地电阻、减小接触电压和跨步电压是一项行之有效的措施。

Grounding Resistance Measurement and Three-Dimensional Grounding Grid

Many power plants and substation are built in mountainous areas or places where the environmental conditions are very bad and the soil resistivity is relatively high. Even built in urban areas, they are subject to limitations on the ground area. Therefore, it is critical that the design of the power plant or substation should be in conformity with the design standard to ensure both human and equipment safety. To begin with, the grounding resistance should be measured accurately; and there are many ways to measure the resistance. This paper discusses the 3-electrode straight line method （0.618 method） and 3- electrode trigonometry method （30° angle） under the ideal ground connection by analyzing the fundamentals of the grounding resistance t in the hope to provide valuable references for the design, construction and measure of the similar project. Practice shows that it will be helpful to decrease the grounding resistance, reduce the touch voltage as well as step voltage by adding vertical grounding electrodes and adopting the new technique of three-dimensional grounding grid.