Arc-flash Assessment for High Voltage Transmission Lines-A BC Hydro Perspective

BC Hydro has recently undertaken a system-wide arc-flash assessment. The calculation of incident energy for the high-voltage transmission lines is challenging primarily due to the lack of (a) established methodologies, (b) understanding of live-line arc hazard scenarios, and (c) published examples of arc-flash studies. This work provides an overview of BC Hydro's current approach in conducting transmission line arcflash hazard assessment. A set of credible scenarios are identified - followed by a discussion of applicable methodologies and input parameters. The incident energy levels are calculated for all transmission voltage classes, from 69 kV to 500 kV. This is done through two types of analysis: (a) sensitivity analysis against fault clearing time and fault current, and (b) line-specific analysis to determine the arc hazards along a line. For the latter, an automated process is outlined to study multiple lines simultaneously. Finally, highlights of the interim results are presented, and areas of further work are indicated.