Modeling method for soil ionization process

Abstract

The invention discloses a modeling method for a soil ionization process, which is characterized in that when the electric field intensity of soil is increased to a critical field intensity Ec, the resistivity of the soil begins to decrease, and when the electric field intensity is smaller than a maintenance electric field Ew, the resistivity of the soil begins to recover. The soil can be divided into an ionization saturation area and an ionization unsaturated area according to the ionization degree of the soil, and after the resistivity of the soil in the ionization saturation area is reduced to the residual resistivity, the resistivity is kept unchanged until entering a recovery process; the soil in the unsaturated region is ionized, and before the resistivity is reduced to the residual resistivity, the electric field is reduced to be below Ew, so that a recovery process is entered in advance. According to the modeling method for the soil ionization process, the influence of the electric field intensity on the resistivity change speed and the transition time of resistivity change are considered at the same time, and the method has reference significance on voltage transient calculation of the grounding body under the impact current.

Description

technical field [0001] The invention belongs to the high-voltage technical field, and in particular relates to a modeling method of a soil ionization process. Background technique [0002] The grounding device plays an important role in ensuring equipment and personal safety, but the voltage response characteristics of the grounding body under lightning current are quite different from those under power frequency. Due to the large amplitude of the lightning current, when the lightning current flows through the grounding conductor, a high electric field intensity will be formed in the soil, which will ionize the soil and reduce the resistivity of the soil. [0003] In the current numerical calculation method of electromagnetic field, finite element and time-domain finite difference are mainly used to model soil ionization. In the finite element method, the soil resistivity is directly related to the electric field, when the soil electric field changes from E 1 change to E ...

AI Technical Summary

Problems solved by technology

If the electric field reaches the discharge field strength from zero instantaneously, the soil resistivity will also instantly change to the metal resistivity, without considering the transition time of the soil change

In the finite-difference time domain method, the soil electric field only determines the moment of resistivity drop, but has nothing to do with the drop rate of resistivity

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