Inadequacies of the Industry-Standard IEEE C37.99-2000 Concerning Grounding Neutrals of Shunt Capacitors in High-Voltage Substations

The industry-standard IEEE C37.99-2000 recommends the use of Peninsula Neutral Ground as the preferred method to ground the neutrals of capacitor banks in high-voltage substations. The basis for this recommendation is a 1972 IEEE paper by Rogers and Gillies that has remained unchallenged until now. Many grounding designs are carried out according to this approach despite the fact that it is the least efficient one. As long as this IEEE standard is not updated to reflect the new findings reported in this paper, designers will continue to be misguided. In this paper, we demonstrate that IEEE standard C37.99-2000 recommendations have no valid scientific basis by comparing the overall performance of a 735/230-kV substation grounding system designed according to the Peninsula Neutral Ground method, the single-point neutral ground and a more conventional design consisting of reasonably dense ground conductors in the 230-kV capacitor banks area and conclude that the conventional design offers superior performance from a safety and electromagnetic-interference perspective based on the fundamental frequency and full frequency spectrum of the back-to-back capacitor switching transient current discharge.