Thermal Impact of Lightning Current Injection into A Floor Housing High-Voltage Substations

Abstract

In this paper the ionization problem of the ground, during the injection of lightning current through the earth of electrical installations is presented; this soil degradation has negative consequences on the performance of the earth electrodes through its transient impedance. To resolve this problem, we analyzed the measured samples of the earth resistance of the Lingwala / Kinshasa HV substation, where the soil is sandy-clay; the model of the dynamics of soil heating for a temperature variation simulated in Matlab gave us satisfactory results characterized by a decreasing exponential of the resistivity of the soil which gives the image of the pre-ionization which means an impedance low-value earth electrode transient which reflects its good performance. These encouraging results are safety indicators for electrical installations; they are aimed particularly at designers of industrial installations, operators of HV substations in electrical networks, and managers of buildings open to the public such as banks, hospitals, and large spaces. Keywords-- Thermal impact; injection; Lightning current; Ground; Job; High tension