REX521 ABB | Legacy Motor & Feeder Protection Relay
Manufacturer: ABB
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Part Number: REX521
Condition：New with Original Package
Product Type: Legacy Motor & Feeder Protection Relay
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Country of Origin: Sweden
Payment:T/T, Western Union
Shipping port: Xiamen
Warranty: 12 months
Product Overview
The ABB REX521 (REX521GHHPLH04G) is a multifunctional feeder protection relay designed for medium-voltage power distribution networks.
It performs protection, control, measurement, and supervision of incoming and outgoing feeders, motor feeders, and busbars. The REX521 also serves as backup protection for transformers and high-voltage line relays, making it ideal for industrial and utility substations.
Although discontinued since 2012, the REX521 remains widely used due to its reliability, robust design, and comprehensive protection functions.
Technical Specifications
| Specification | Details |
|---|---|
| Model Number | REX521 |
| Product Type | Feeder & Motor Protection Relay |
| Function | Protection, control, measurement, supervision |
| Application Areas | Medium-voltage networks, motor feeders, busbars, substations |
| Protection Functions | Overcurrent (3I>, 3I>>), earth fault, phase unbalance, thermal overload |
| Measurement Inputs | Conventional CTs and VTs or sensor-based inputs |
| Communication Protocols | IEC 60870-5-103, Modbus, SPA-bus |
| Mounting | Panel-mounted |
| Display | LCD with LED indicators |
| Event Recording | Yes, with time stamping |
| Disturbance Recorder | Yes – waveform capture |
| Power Supply | 24–250 V DC or 100–240 V AC |
| Operating Temperature | –10°C to +55°C |
| Standards Compliance | IEC 60255, ANSI, CE |
| Country of Origin | Switzerland |
FAQ
Q1: Is the ABB REX521 still available?
A1: Yes, the REX521 is a legacy product but available from stock as a new or tested unit.
Q2: What protection functions does it provide?
A2: It protects against overcurrent, earth faults, phase unbalance, and thermal overload.
Q3: Which protocols does the REX521 support?
A3: The relay supports IEC 60870-5-103, Modbus, and SPA-bus communication.
Q4: What is the power supply requirement?
A4: It operates on 24–250 V DC or 100–240 V AC, depending on installation.
Q5: Can it be used in motor feeder and substation applications?
A5: Yes, it is designed for medium-voltage networks, motor feeders, busbars, and substations.