SEL-3505/SEL-3505-3 Real-Time Automation Controllers (RTACs)

Suitable for use in utilities and industrial environments, the SEL-3505/3505-3 Real-Time Automation Controllers (RTACs) are a lower voltage version of the SEL-3530 RTAC. The SEL-3505/3505-3 RTACs are compact and deliver all the standard features of an RTAC, making them excellent options for protocol conversion and secure communication when space is limited.

Transmission Protection

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

Apply the SEL-411L Relay for 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.

SEL-421 Distance Relay

Apply the SEL-421 Protection, Automation, and Control System for high-speed distance and directional protection and complete control of a two-breaker bay. Protect any transmission line using a combination of five zones of phase- and ground-distance and directional overcurrent elements.

SEL-311L Line Current Differential Protection

Use the SEL-311L Line Current Differential Relay with integral four zone distance backup for easy-to-apply, high-speed line protection. Apply subcycle current differential protection with included four zone distance and directional overcurrent backup. Use single or dual differential channels for reliability.

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 protection, reclosing, monitoring, and control of transmission lines. Features include a four-shot recloser, patented capacitance voltage transformer (CVT) transient overreach logic to enhance security of Zone 1 distance elements, and overcurrent elements.

Recloser Control Products

Recloser controls are the front line of the distribution power system, often located in distribution substations or on feeders, recloser controls supply the intelligence to allow reconfiguration of distribution systems and maintain reliable service to as many people as possible in the event of a fault.

SEL-351R Recloser Control

The SEL-351R Recloser Control, derived from SEL’s premiere distribution relay, the SEL-351 Protection System, combines traditional recloser control functions with technologically advanced SEL relaying features, such as phase and ground directional elements, multilevel under- and overfrequency trip and control, and high-accuracy metering.

SEL-651R Advanced Recloser Control


Apply the easy-to-use SEL-651R Advanced Recloser Control for Automatic Network Reconfiguration, three-phase and single-phase tripping, and all your distribution automation needs.