Calculation of Tower Impulse Grounding Resistance
Hua Xu · Gao dianya jishu · 2006
By mathematical model,using optimum method-variable metric method,this paper establishes object function,and accurately solves parameters of double exponential function.By Fourier series,this paper transforms double exponential function into the sum of many sinusoidal functions.And high amplitude lightning current is fed to grounding grids,spark discharge will be generated.The paper substitutes the spark discharge of soils with the increment of the equivalent radius of grounding branch.When equivalent radius of branch are very large,the paper introduces the influence of equivalent radiuses on the depth of embedment of grounding branch.By field-circuit coupling theory,the parameters in impulse current of grounding grids are obtained by using nodal voltage method.The whole calculations are a gradually approximate process.The paper computes some specific cases,and presents some reference for practical engineering.