SEL-311C

The SEL-311C is a distance protection relay designed for overhead lines and cable feeders that require high-speed impedance-based fault detection. It provides multiple zones of distance protection with quadrilateral or mho characteristics, load encroachment logic, and power-swing blocking for stable operation. The relay supports permissive/blocked pilot schemes using POTT, PUTT, DCB, and DCUB logic. SEL-311C also includes synch-check, reclosing, fault location, and extensive automation through SELogic. It integrates with SCADA systems via IEC 61850, DNP3, and multiple telecom channels. With a proven track record in utilities worldwide, SEL-311C ensures reliable protection in demanding grid conditions.

Key Features

• Multi-zone distance protection

• Pilot schemes (POTT, DCB, DCUB, PUTT)

• Power swing detection and blocking

• High-accuracy fault location

• IEC 61850 communication

• SELogic automation control

Applications

• Transmission line protection

• Sub-transmission and long feeders

• Pilot-wire and teleprotection schemes

• Backup for line differential relays

Keywords

SEL-311C, distance relay, impedance protection relay, line protection, SEL distance relay