Worker Safety Considerations for Deployment of Mobile Disconnect Switches on Transmission Lines

Mobile disconnect switches allow electrical isolation on high voltage transmission lines where stationary switches are not available, or special switching is required. In particular, dropping/picking part of a line and loop switching are two key applications of mobile switches. These switches are used in live-line environment. Therefore, several worker safety considerations must be taken into account prior to their deployment. Electrical clearance, grounding design, switch duty calculation and switching sequence - all needs to be assessed. This article provides a set of simplified methods for initial calculations, and an example of real-world deployment where many of these issues are addressed.