Evaluation Method of Nano-Carbon Fiber Grounding Grid Considering Short Circuit Current Distribution-Part I: Selection and Calculation of Parameters

Due to its excellent corrosion resistance and the electrical conductivity is superior to other nonmetal materials, carbon nanofibers material has become the development direction of the grounding material. However, as a new type of nonmetal grounding material, the electrical properties of carbon nanofibers material has not been fully studied. In addition, the existing rules are based on the metal grounding grid, and the resistivity and thermal stability of carbon nanofibers material are different from the metal materials, therefore, reasonable calculation of grounding parameters and evaluation of carbon nanofibers grounding grid is of great significance to the application and promotion of carbon nanofibers and nonmetal grounding material. Due to the high resistivity, low permeability and low coefficient of thermal stability of nano-carbon fiber material, the evaluation method of nano carbon fiber grounding grid is different from that of metal grounding grid. This paper analyses safety assessment methods of nano-carbon fiber grounding in detail from the conductor cross-sectional area and equivalence, the short-circuit current calculation and the grounding parameters calculation, to provide reference for the evaluation of nano-carbon fiber material and various non-metallic materials. At the same time it lays a foundation for the application of nonmetal material in power frequency grounding field.