ABB REF543KM127AAAA Medium‑Voltage Feeder Protection & Control Terminal

Product Description

REF543KM127AAAA belongs to ABB REF543 series feeder terminal, an integrated multifunctional relay for medium‑voltage switchgear protection, measurement, control and supervision. 

It implements overcurrent, earth‑fault, over‑voltage, under‑voltage and thermal overload protection, supports built‑in PLC logic for substation automation sequence control.

 Equipped with rich communication interfaces for connecting to higher‑level SCADA system. Widely applied in power plant auxiliary systems, industrial distribution networks and utility 

substations. This device is end‑of‑life legacy maintenance spare‑part.

Technical Specifications

Full Model: REF543KM127AAAA

Brand: ABB, Origin: Finland

Product Family: REF543 Series

Module Type: Medium‑Voltage Feeder Terminal / Protection Relay

Input & Output: 25 binary inputs,18 relay outputs

Communication: SPA‑Bus, LON‑Bus, IEC60870‑5‑103, DNP3.0, Modbus, IEC61850 supported via external adapter

Auxiliary Supply: 85‑265 VAC / 88‑300 VDC

Operating‑Temperature: ‑20℃ ~ +60℃

Storage‑Temperature: ‑40℃ ~ +85℃

Ambient Humidity: 5%‑95% non‑condensing

Net Weight: Approx. 7.7 kg

Product Status: Discontinued / Obsolete

 Key Features

All‑in‑one protection, measurement, control and condition‑monitoring for MV feeder application

Rich protection functions including overcurrent, earth‑fault, thermal overload and fault‑locator

Embedded programmable PLC logic reduces external hard‑wiring for bay‑level interlock

Multiple standard industrial communication protocols for substation SCADA integration

Supports measurement via traditional CT/VT or modern current‑voltage sensors

Robust hardware for cabinet installation in industrial and utility power‑system environments

Critical spare‑part for refurbishment and maintenance of existing REF543‑series substation equipment