Observation and analysis of the sparkover around grounding electrode under impulse current. Issue 8 (26th May 2017)

• Record Type: Journal Article
• Authors: Lu, Hailiang; Feng, Zhiqiang; Tong, Xuefang; Chen, Wenguang; Tan, Bo; Wen, Xishan
• Is Part Of: IET generation, transmission & distribution. Volume 11:Issue 8(2017)
• Page Start: 1997
• Page End: 2002
• Publication Date: 2017-05-26
• Subjects: sparks -- trees (electrical) -- electric current measurement -- electric fields -- earth electrodes; grounding electrode -- impulse current -- soil sparkover -- polyester‐based sensitive films -- sandy sparkover -- horizontal grounding rod -- current distribution -- modular multichannel simultaneous signal acquisition system -- spark discharge -- electrode‐like cluster -- tree creeping discharge -- current measurement -- electric field distribution -- electric field intensity; Electric power production -- Periodicals; Electric power transmission -- Periodicals; Electric power distribution -- Periodicals; 621.3105
• DOI: 10.1049/iet-gtd.2016.1452
• Languages: English
• ISSNs: 1751-8687

Abstract

Abstract : Soil sparkover is one of the key factors that affect the impulse characteristics of grounding devices under lightning current. In this study, the polyester‐based sensitive films are applied to observe the morphology features of the sandy sparkover around a horizontal grounding rod 1 m in length buried in a hemispheric pool 8 m in diameter under impulse current. Moreover, the releasing current distribution of the grounding rod is measured by modular multi‐channel simultaneous signal acquisition system. Along with injected impulse current increasing, the ratio of current released from two ends of the rod increases because the spark discharge leads the redistribution of the dissipating current. The discharge in the sand becomes more intense with current increasing. The discharge on middle segments spreads around the electrode‐like cluster, while sparkover at the terminal develops into tree creeping discharge finally. Analysis based on combining observation images with current measurement result suggests that sparkover morphology is related to not only electric field value but also electric field distribution. The sparkover strength is determined by electric field intensity, while the sparkover concentration depends on electric field uniformity.