Line protection relay Schweitzer Engineering Laboratories
Protect lines with easy-to-use current differential relays. Sensitive differential elements provide sub-cycle operating time. Restraint for external faults uses an easy-to-set vector ratio of remote and local currents. Protect transmission lines using differential and a combination of four stepped-distance zones of phase and ground-distance elements in communications-assisted schemes, with directional overcurrent element backup protection. Patented Capacitance Voltage Transformer (CVT) transient overreach logic enhances security of Zone 1 distance elements. Best Choice Ground Directional Element™ logic optimizes directional element performance and requires no directional settings. Use the optional single-pole tripping capability of the differential elements to improve system stability. Programmable four-shot breaker auto-reclose with synchronism and voltage check logic for optimal system restoration.
