Substation grounding studies with more accurate fault analysis and simulation strategies

This paper describes hands-on modeling and simulation experience for designing substation ground grids. The grounding studies enable an optimized ground grid design to protect utility personnel and the public. These optimized ground grids meet the IEEE-80 standard [1] for safety and have been simulated and designed using more accurate transient and steady-state fault current calculations. The SI and MI methods are used to simulate the actual fault locations and fault currents at a small station and a large EHV station, respectively. The simulations primarily focus on substation specific data for the application rather than utilizing pre-determined split-factor curves and the decrement-factor table in IEEE-80. In addition, the new clearing time analysis and grounding study safety assessment strategy will be implemented instead of using the widely-applied longest clearing time and its corresponding threshold calculation, which could further optimize the ground grid. With AEP's research and applications, the authors hope it can benefit similar industrial substation design projects.