SEL revolutionized the protection industry by building the first microprocessor-based protective relays. These relays integrated, economized, and simplified the art of transmission line protection while introducing two powerful tools: fault locating and event reporting.
- SEL-411L Advanced Line Differential Protection, Automation, and Control System
The SEL-411L offers complete protection and control of any transmission line. The SEL-411L provides differential protection with both phase- and sequence-based operating elements for sensitivity and high-speed operation. Accurately pinpoint faults with optional GPS-synchronized traveling wave fault location. Save time and money by sending maintenance crews to the tower nearest the fault.
- SEL-421 Protection, Automation, and Control System
Protect transmission lines with high-speed distance and directional functions.
- SEL-311L Line Current Differential Protection and Automation System
Use the SEL-311L Relay with integral four-zone distance backup for easy-to-apply, high-speed line protection.
- SEL-387L Line Current Differential Relay
Use SEL-387L Line Current Differential Relays for economical, easy-to-apply line protection.
- SEL-311C Transmission Protection System
Apply the SEL-311C Relay for complete protection, monitoring, and control of transmission lines.
- SEL-321 Phase and Ground Distance Relay
The SEL-321 Relay delivers outstanding EHV protection, performance, and features—at a price practical for all voltage levels and with the features you need for system integration.
- SEL-321-5 Phase and Ground Distance Relay
Select the SEL-321-5 for 50 Hz applications requiring enhanced single-pole tripping, phase and ground distance, directional overcurrent, and negative-sequence protection.