A Case Study On Distribution Bus Protection Improvements

This case study presents a history of distribution bus protection at Upper Cumberland Electric Membership Corporation (UCEMC) and the various bus faults that led to redesigning bus protection. An enhanced bus protection scheme was applied during station protection modernization as well as through existing protective relaying where applicable. Multiple real-world events and site media are analyzed both prior to and after protection upgrades, showing significant protection improvement for similar bus faults. One long-clearing event prior to the enhanced scheme shows simultaneous faults with arcs travelling from the bus into a feeder. Additional considerations include downstream IBR and the impact it has on enhanced bus protection schemes.