Line Protection
SEL products lead the industry in reliability. That’s one reason why we’re North America’s most trusted relay manufacturer and a world leader in transmission line protection.
SEL line protection solutions are ideal for improving system stability and security, allowing you to:
- Securely apply distance protection elements and implement communications-assisted tripping.
- Apply line current differential protection to protect long transmission lines and complex systems.
- Connect weak sources (e.g., wind farms) and inverter-based generation to the utility grid.
- Locate faults faster and more precisely with the traveling-wave technology in select SEL transmission relays.
- Simplify protection schemes and enable faster, more secure tripping with time-domain technology.
With feature-rich SEL relays, you can apply protection, fault-locating, and monitoring solutions with a single piece of equipment. This saves money, increases efficiency, and improves reliability by reducing wiring and configuration complexity.
Distance Protection
Apply distance protection as a primary protection solution or as a backup to line current differential schemes. SEL relays can be securely applied on short lines and under heavy load conditions, with or without wide-area communications. Zero-setting out-of-step blocking functions improve system stability without time-consuming and expensive system studies.
Line Current Differential Protection
Use line current differential protection for improved protection of your most critical transmission lines. It’s an ideal solution for long extra-high-voltage lines, for complex systems where distance protection alone is inadequate, and for primary line protection when connecting wind farms to the grid.
Fault Locating
The fault-locating functions built into SEL relays ensure that you can dispatch crews to precise locations and repair the faulted section quickly. SEL relays can compute fault locations using multiple methods—including traveling-wave fault locating, which locates faults to within one tower span.
Time-Domain Line Protection
Deploy innovative SEL time-domain protection products to simplify protection schemes and enable faster, more secure tripping.
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.
Questions? Contact Us!
We’re happy to answer all your questions and help develop the best solution for your needs.
Unbeatable Support
Every SEL solution comes with lifetime technical support, free of charge.
There are no service contracts, time limits, or expiration dates. No matter how often you call or how long your SEL products have been in service, you’ll reach a friendly human who can provide the service and support you need.
Our 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. We’re always ready with the information and resources needed to keep your SEL solution working effectively.