SEL Expands Transformer Differential Protection

Schweitzer Engineering Laboratories, Inc. has announced three new additions to the popular SEL-787 family of differential protection relays.

Feb. 17, 2015

2 min read

Schweitzer Engineering Laboratories, Inc. has announced three new additions to the popular SEL-787 family of differential protection relays, providing low-cost, versatile transformer differential protection for an expanded range of applications.

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The new relays (SEL-787-3E, -3S, -4X) offer the following benefits for transformer protection:

Protection for transformers in 2-, 3-, or 4-terminal applications using one relay family, keeping schematics simple and minimizing the learning curve
Expanded capability to apply current differential, voltage, frequency, and/or thermal-based protection functions
Sensitive detection of internal faults near the grounded neutral with as many as three restrictive earth fault (REF) elements

“Customers can now use the SEL-787 to protect transformers in up to four-terminal differential applications and can standardize on a single transformer protection platform to reduce business and operation costs,” said Dave Whitehead, SEL vice president of R&D. “We have also added Spanish language support in the new SEL-787 relays that includes the acSELerator^® software, front-panel overlay and relay scripting, allowing Spanish-speaking engineers and technicians to quickly configure and use the relays.”

The additional 4 pushbuttons and 16 tricolor LEDs on the front panel, all of which are programmable, quickly inform operators and support efficient local or remote control. Similar to the existing SEL-787, there are two slots available for additional I/O cards. The IEC 60870-5-103 protocol is also available as an option. The SEL-787-3E, -3S and -4X are available to order today.