On the Issue of Design of Grounding Systems of 330(220) Kv Substations to Ensure the Electromagnetic Compatibility of Secondary Circuits

Abstract

The purpose of the work is to develop the fundamentals of the design methodology of grounding system design of substations with open switchgears 330 (220) kV, which is aimed at ensuring electromagnetic compatibility of secondary circuits of current transformers. Methodology. To carry out the research, the provisions of the theory of experiment planning, the theory of electrical circuits, mathematical modeling in the package Grounding 1.0 and Microsoft Excel were used. Results. During the onefactor experiments, the dependencies of the grounding system resistance and the voltage between the calculated points on the grounding system area, the size of the grid cell, the perimeter of the grounding system horizontal electrodes cross-section, the equivalent soil resistivity, the short-circuit current and the design factor were obtained. It is shown that the grounding system resistance and the voltage between the calculated points are practically independent of the depth of the horizontal electrodes in the depth range from 0.4 m to 1.4 m. Originality. The paper formulated three criteria for grounding system designing of substations 330 (220) kV, aimed at ensuring electromagnetic compatibility of secondary circuits. Practical value. The fundamentals of the methodology for grounding system designing are formulated according to the criterion of preventing false triggering of relay protections in emergency modes. References 10, tables 2, figures 14.

Overvoltages during Single-Phase Earth Fault in Neutral-Isolated Networks (10÷35) kV

“…where the potential of point 1 will change in accordance with the operating frequency of the energy source, and the potential of point 2 will change in accordance with the special frequency ω 0 of the "3C f -L c " circuit. As a result, the restored voltage in the span of the arc will change accordingly in expression (7) [9,10].…”