If you have transmission system challenges that you need to solve—no matter how complex—SEL is ready with the products and expertise you need.

Our solutions focus on the first principles of protection, augmented by automation and monitoring capabilities, wide-area communications, and industry-leading traveling-wave technology.

SEL is recognized as North America’s most trusted relay supplier and a world leader in transmission protection—a position of trust we’ve earned over decades of dedicated service to the electric power industry. We bring industry-leading reliability and support to customers around the world.

Line Protection

Our distance protection and line current differential relays feature advanced protection logic that increases reliability and allows flexible application. And SEL relays with time-domain and traveling-wave technology are setting new standards for fast, secure tripping decisions and precise fault location.

Bay Control and Substation Integration

SEL provides complete monitoring and control solutions for all of your mission-critical substation equipment, including double breakers, reclosing, breaker failure, and auxiliaries such as air break switches, grounding switches, and more.

Digital Secondary System (Digital Substation) Solutions

SEL digital secondary system solutions—commonly called digital substation solutions—help protect and control a substation’s primary equipment. This type of system transmits data via fiber-optic cables from remote field modules in the yard to relays in the control house. Pick the solution that fits your application.

TIDL Technology: An SEL Innovation

Time-Domain Link (TiDL) technology is an innovative, protection-centered solution engineered with simplicity in mind. It uses a point-to-point architecture, secure direct fiber connections, and built-in time synchronization, making it easy to implement with no network engineering required.

Sampled Values Technology

SEL Sampled Values (SV) solutions combine protection in the merging units with the flexibility of IEC 61850-9-2 communications. It is a communications-centric, standard-compliant solution that uses a point-to-multipoint Ethernet-based network to transmit data.

Monitoring and Automation

Control and optimize every aspect of power system protection and operation to improve performance and resiliency.

Synchrowave Operations: The Next Step in Situational Awareness

Visualize and monitor your entire transmission system—so you never have to wonder what’s happening with mission-critical functions and equipment. SEL Synchrowave Operations software works seamlessly with all SEL transmission protection devices to turn the advanced data they collect into information you can use.

Engineering Services

Let us partner with you to create an SEL solution for your system. From engineering studies and system design through commissioning and training, SEL engineers bring inventiveness and a deep understanding of the fundamental principles of electric power systems to every project. No matter how complex or sophisticated the system, we can help you protect, simplify, and control it.

Products and Service You Can Rely On

SEL products are designed and manufactured for the world’s most challenging environments, exceeding all industry standards for temperature, shock, and electric stress. An optional conformal coating for circuit boards adds an extra level of protection against contaminants in extreme environments.

Every SEL product comes with a ten-year warranty—the best in the industry. If any product fails under warranty, we’ll repair or replace it for free.


SEL University, Conferences, Tradeshows, Seminars

SEL meets your immediate and long-term workforce education needs by offering SEL University courses, seminars, conference presentations, and attending tradeshows.

Questions? Contact Us!

If you have any questions about SEL products, services, solutions, or support, please contact us. Our service and support professionals are ready to provide the answers you need.

Unbeatable Support

SEL support teams are stationed in regional offices around the world and staffed with application engineers who are experts in our products and in power system applications.

Technical support for SEL-manufactured devices is always free. No matter how often you need to call or how long your SEL products have been in service, you’ll reach an SEL expert who can provide the service and support you need.

Our cybersecurity team is always ready with the information and resources needed to keep your OT networks and critical systems secure and working effectively. Cyber services support contracts can include incident response, audits, system hardening, and more, depending on your anticipated needs.

More about SEL warranty and support