Considerations in the design of electrical substations, including the effect of potential gradient on surrounding metallic structures

Abstract

For designing and studying an electrical substation grounding system [GS], a simple remote substation is considered according to the safety procedures indicated in the IEEE 80 Standard. Buried metallic materials or nearby metallic structures permanently endanger human life when electrical faults occur. Scenarios related to the design of electrical substations that consider the transfer of electrical potentials that can occur between the GS and buried metallic materials in their vicinity are presented, the behavior of potential transfer is evaluated, values of transferred voltages are calculated, and the main variables that influence the transferred voltage levels are identified. The simulations are performed with the CYMGRD software specific for GS calculations. Its analysis generates real results in the potential transfer that must be considered by the GS design engineer, which enables to avoid designing isolated substations without taking into account existing elements that may affect the substation surroundings.

Keywords

• Electrical substation
• grounding systems
• ground grid
• potential transfer
• step and touch voltage
• buried metal structures