The document describes the features and characteristics of the Busbar differential protection IED REB 670, including the three-phase and single-phase versions of the differential protection zones, low-impedance differential protection zones, and CT input quantities.
The REB 670 is an intelligent IED designed for fast, selective differential protection of busbars, T‑connections and meshed corners in medium, high and extra‑high voltage substations. It offers two low‑impedance differential zones, high‑speed tripping (typical 12 ms) and extensive self‑supervision, with flexible CT ratio handling and optional breaker‑failure and over‑current functions.
The document describes the three‑phase (A20, A31) and single‑phase (B20, B21, B31) variants, pre‑configured options X01‑X03, communication modules (IEC 61850‑8‑1, IEC 60870‑5‑103, LON, SPA, optional GPS) and detailed configuration possibilities for various substation topologies.
| Number of differential protection zones | Two low‑impedance zones |
|---|---|
| Typical operating time for internal faults | 12 ms |
| Analog measurement accuracy | Below 0.25 % for current and voltage |
| Maximum analog and binary signals recorded | 40 analog, 96 binary |
The typical operating time for internal faults is 12 ms.
The A31 three‑phase variant provides eight three‑phase CT inputs.
Analog measurements are accurate to below 0.25 % for both current and voltage.