Open AccessImpact of Lightning Protection Grounding System on the Ground Surface Potential of Substations
Author(s) -
Tingji Chen,
Lingfeng Yang,
Wanmiao Gu,
Haiyang Gao,
Junchi Zhou,
Xiaodong Fu
Publication year - 2022
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/2148/1/012049
Subject(s) - ground , earthing system , lightning (connector) , roof , engineering , lightning strike , electrical engineering , structural engineering , power (physics) , physics , quantum mechanics
Grounding device is an indispensable facility for lightning protection of buildings. Nowadays, SGCC (State Grid Corporation of China) is promoting steel structure substations, which are made of metal as a whole including the roof. There are now several grounding approaches when the roof was struck by a lightning flash, including external grounding, nearby grounding, separate grounding and common grounding. This paper took a metal structure substation in Nanjing as an example and calculated its ground potential in case of different grounding system. We came to such conclusions: 1) For substations of separate grounding system, the ground potential after a lightning strike could reach as high as 743.5kV and 230kV with a single earthing electrode and multiple electrodes respectively. 1000μs after the strike, the ground potential is 91.57 kV, which is still a significant threat to humans and equipment inside. 2) Nearby grounding and external grounding are both common grounding system. The peak of ground potential after a lightning strike is 101.4kV and 109kV respectively, much lower than that of separate grounding system. They also have similar waveform and peak time. 3) 3500μs after the lightning strike, the ground potential all over the grid is around 36V. 4) Separate grounding is not a sound choice of grounding system for steel structure substations. From the perspective of cost and discharging capacity, nearby grounding is the most reasonable scheme for a steel structure substation.