Technical and economical ground electrode design in various soil and depth in HVDC system by analyzing voltage distribution by FEM

Abstract

Bi-polar and mono-polar HVDC systems with ground return path is a commonly used configuration. One of the main concerns of this type of system is grounding electrode. Safety of the people near the grounding system is important and the voltage rise during operation should be limited within safe portions. On the other hand, dimension and cost of the grounding system installation play important roles. Minimum ground electrode size and lower burial depth will lead to minimum costs. An optimum design of grounding system can fulfill both technical and economical purposes. This paper covers a method for designing the ground electrode for HVDC systems. This method will be applied for designing a ring type ground electrode as a case study. Different resistivity of soil and various ground electrodes are modeled in detail and a FEM based engineering method is applied to solve the voltage distribution problem and achieve desire surface voltage. Effects of soil resistivity, burial depth and radius of the electrode on voltage distribution will be studied.