不同结构土壤中接地网冲击特性的测量与分析

变电站接地网的冲击特性研究对于接地网的优化设计具有重要意义,为能系统真实反映接地装置在不同土壤结构中的冲击特性,基于量纲相似性原理,利用冲击电流发生器进行了接地网在均匀及双层土壤中的冲击接地模拟试验。在均匀土壤中测量了5种埋深、3种冲击电流注入点位置时对应的接地网冲击接地电阻值,并测量了典型情况下接地网的地表电位分布情况;在双层土壤中测量了3种土壤厚度、3种冲击电流注入点位置时对应的接地网冲击接地电阻值。通过分析不同试验条件下接地网模型的冲击接地电阻及电位分布得到了冲击电流注入点位置、地网埋深及土壤结构等因素对接地网的冲击接地特性的影响规律。

Measurement and Analysis of Impulse Characteristics of Grounding Grids in Different Soil Structures

In order to find the correct impulse characteristics of the grounding grids systematically and factually,impulse grounding experiments are carried out by employing impulse current generator in uniform and two-layer soils which is based on principle of dimension similarity.This test mainly measured impulse grounding resistance in uniform soil with five different embedment depths and three different current-injected points,potential distribution on the surface of uniform soil and impulse grounding resistance in two-layer soil with three different upper depths and three different current-injected points.The experimental results indicate that the factors such as current injection location,grid depth and soil structure have influences on the impulse characteristics of the grounding grids,and the influence regulations are described.