# SEL-787 Transformer Protection Relay

> transformer-protection - Two-winding transformer differential, overcurrent, thermal replica, restricted earth fault and through-fault recording

**Voltformer canonical:** https://voltformer.com/product/sel-787-transformer-protection-relay - markdown version: https://voltformer.com/product/sel-787-transformer-protection-relay.md

## Overview

- **Brand:** SEL
- **Product family:** SEL-700 Series
- **Application:** Two-winding transformer differential, overcurrent, thermal replica, restricted earth fault and through-fault recording
- **Product type:** transformer-protection

## Protection & Control Functions

- **ANSI Functions:** 87T, REF/87N, 49, 50/51, 50N/51N, 24, 50BF, 27/59
- **Transformer Windings:** 2
- **Supports Transformer:** Yes
- **Supports Feeder:** No
- **Supports Breaker Control:** Yes
- **Arc Flash Protection:** No

## Digital Integration & Protocols

- **IEC 61850 Edition:** Ed2
- **GOOSE:** Yes
- **Sampled Values (SV):** Yes
- **Redundancy (PRP/HSR):** Yes (PRP/HSR)
- **Protocols:** IEC 61850, DNP3, Modbus, Mirrored Bits
- **Engineering Software:** acSELerator QuickSet

## Electrical Interface

- **Frequency:** 50/60 Hz
- **Nominal Current:** 1 A / 5 A
- **Auxiliary Supply:** 24–48 / 110–250 Vdc options
- **Operating Temperature:** -40 to +85 °C

## Standards

- IEC 60255
- IEEE C37.90
- UL Listed

## Sources

- https://selinc.com/products/787/

- **Source scope:** manufacturer-family
- **Last reviewed:** 2026-09-13

Manufacturer portfolio/family source. Confirm the exact order code, guaranteed ratings and project-specific options against the current OEM datasheet before procurement or an SLD study.

Technical ratings are configuration-dependent where stated by the manufacturer. Request project-specific verification before procurement.