PAC World magazine
Authors: M. Mohemmed, Scottish & Southern Electricity Networks (SSEN), UK, P. Orr, S. Blair, N. Gordon, I. Mckeeman, Synaptec, UK, A. Mohamed, ScottishPower Renewables, UK, and A. Bonetti, Megger, Sweden.
Date published: March 2023
Abstract
New grid connections for low-carbon technologies can lead to costly engineering work to install and protect the resulting complex, multi-ended circuit. Circuit protection for multi-ended feeders is conventionally implemented via line differential or distance protection. However, each option has drawbacks. Line differential protection requires a protection relay at each feeder-end with reliable alignment of current measurements, plus a robust telecommunications infrastructure. This duplication of equipment at each line end results in significant total costs and, in older substations, space constraints can be a limiting factor.
Operators seeking to protect multi-ended circuits are therefore often required to utilize distance protection, resulting in complex setting calculations, reduced resilience (due to the under-reaching effects caused by fault infeeds from teed circuits), and increased operation time of the scheme.