Line Protection

SEL line protection solutions are ideal for improving system stability and security, allowing you to:

• 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.
• Securely apply distance protection elements and implement communications-assisted tripping.
• Apply line 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.

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.

Apply distance protection as a primary protection solution or as a backup to line 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.

Use line 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.

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.

Deploy innovative SEL time-domain protection products to simplify protection schemes and enable faster, more secure tripping.