Study on the influence law of typical soil parameters based on discharge morphology on critical breakdown field strength

Abstract

The phenomenon of partial discharge of soil that occurs when a lightning current enters the ground through a ground electrode poses a threat to the safety of personnel and equipment. The strength of partial discharge and the formation of soil discharge channels are closely related to the magnitude of the critical breakdown field strength. Therefore, how to accurately obtain the variation law of the critical breakdown field strength of typical soil is the key to realize the safe operation of the grounding device and the cable in the ground and ensure the safety of personnel and equipment. In this paper, a simulation experiment of soil impact characteristics is used to study the variation law of typical soil critical breakdown field strength with soil properties. X-ray transmission imaging technology is used to obtain the morphology of the discharge channel, and its non-intrusive observation method will not disturb the discharge channel itself, making the measurement more accurate. This paper first selects a variety of typical soils to study the influence of soil moisture, salt content, compactness and other factors on the discharge channel morphology, and then studies the calculation method of the critical breakdown field strength of the soil under different discharge channel morphologies. And further explore the reasons for the influence of typical soil media factors on the critical breakdown field strength. The experimental results show that under the same conditions, the relationship between the critical breakdown field strength values of different soils is: Ec of sandy soil <; Ec of loam soil <; Ec of pastoral soil; It is precisely because of the different reasons that different factors of the soil medium affect the critical breakdown field strength, the content of water and air inside the soil and the conductivity of the soil are different, so that the variation law of the critical breakdown field strength is different.