Testing through Fall of Potential with High Current Injection in Grounding System in Transmission Line of 500 kV of Santo Antonio HPS

Abstract

This paper presents the application of grounding resistance measurement by fall of potential with high current injection, applied to the Transmission Line (TL) of 500 kV of Santo Antonio Hydroelectric Power Station (HPS), located in the city of Porto Velho/RO, for the commissioning of the power house grounding system in Generation Group (GG2) and TL during construction of the referred project. Based on measurements obtained in field, computer simulations were performed to assess the effectiveness of the grounding system on future fault scenarios of the TL, as well as the suitability of relevant protection functions. The computer simulations are based on the model developed for TL 500 kV of GG2, and are performed using the PSCAD/EMTDC software, including the grounding values derived from the design of high current injection, according to (IEEE Std 80-2013). In order to attest the efficacy of both GG2 grounding system and TL from the HPS, COMTRADE files, obtained by the software, were used in the simulator Doble 6150 for the design of distinct fault conditions in a SEL-421 relay. Results indicate the correct functioning of relay SEL-421, corroborating the effectiveness of both grounding system and measurement method.