Affects of substation interference on low burden intertrip send and receive devices

All devices in substation environments are susceptible to interference from various sources, such as adjacent power conductors, substation heating supplies running in close proximity to DC wiring, to presence of battery earth fault. Selection of appropriate tripping / intertripping devices is of paramount importance to avoid undesirable protection mal-operations. This paper discusses when and where tripping devices, such as opto inputs and tripping relays, should be used to ensure secure and reliable protection systems.