Description
The ABB REX521GHHPLH07G is a multi-functional, microprocessor-based digital protection and control relay belonging to the ABB RE 500 series platform. It is primarily engineered for protection, control, measurement, and supervision tasks within medium-voltage distribution sub-stations, industrial networks, and utility feeders operating at 6–35 kV. Utilizing a modular hardware design and an expandable software library, this unit integrates standard protective functions alongside local control logic (IEC 61131-3) and diagnostic fault recording.
Commercial Availability & Procurement Profile
- Product Status: Legacy / Supported Phase (Active production by the OEM has concluded; primarily sourced through authorized inventory networks).
- Condition: Factory Sealed / New Surplus or Fully Refurbished (100% bench-tested and diagnostic cleared options).
- Warranty: 12-Month Comprehensive Industrial Technical Warranty.
- Logistics: In Stock (Dispatched within 24–48 hours for global shipping).
- Pricing Note: Catalog pricing is indicative. Pricing fluctuates based on current global inventory availability for legacy system components. Contact our technical sales engineering desk for a firm, itemized quotation.
Technical Specifications
The exact character sequence of the model code REX521GHHPLH07G designates a specific hardware combination and firmware level built to the following criteria:
| Parameter | Value / Specification |
| Manufacturer | ABB Power Automation |
| Model Designation | REX521GHHPLH07G (RE 500 Relay Family) |
| Analog Inputs (GHH) | 4 Current Inputs (1 A/5 A dual-compatible CT inputs) + 4 Voltage Inputs (0–120 V AC VT inputs) |
| Auxiliary Supply Range (P) | Wide input range: 80 to 265 V AC / V DC nominal |
| Hardware Variant (L) | Medium I/O configuration (Typically 8 Digital Inputs / 6 Relay Outputs) |
| System Frequency (H) | Adaptive 50 Hz / 60 Hz rating |
| Firmware Level (07G) | Software Revision 07 Profile G baseline standard |
| Measurement Accuracy | Currents/Voltages within \pm0.5\%; Power/Energy within \pm1\% |
| Enclosure Rating | IP54 for front panel faceplate when flush mounted |
| Operating Temperature | −25 to +70°C (−13 to +158°F) continuous |
Protection Functions & Network Integration
The software configuration block executes a massive suite of protective algorithms configured via the ABB PCM600 or CAP505 engineering utilities:
- Overcurrent Protection (50/51/67): Three-stage non-directional and directional phase overcurrent elements with selectable inverse definite minimum time (IDMT) or definite time (DT) delay characteristics.
- Earth Fault Protection (50N/51N/67N): High-sensitivity residual overcurrent tracking for isolated, earthed, or compensated grid topologies.
- Voltage & Frequency Metrics (27/59/81): Continuous monitoring of overvoltage, undervoltage, residual overvoltage (U_0), and underfrequency/overfrequency shift patterns.
- System Automation: Multishot Autoreclosing functionality (79), circuit breaker failure protection (50BF), and integrated sync-check mechanisms (25).
Communication Architecture
The backplane interfaces house dual communication slots allowing parallel SCADA telemetry and engineering access. It natively supports Modbus RTU, SPA bus, or IEC 60870-5-103 protocols over dual RS-485 interfaces. Depending on optional internal module configurations, certain revisions support fiber-optic transceiver loops to eliminate electromagnetic interference across network segments.
Field Installation & Retrofit Constraints
When deploying the REX521GHHPLH07G as a drop-in replacement or integrating it into an existing control panel, engineers must observe the following technical constraints:
- Logic Mapping Transference: Protective thresholds and internal IEC 61131-3 graphical logic paths are stored in non-volatile flash memory. When replacing an inoperative module, you must upload the application configuration (
.pcmpor.cwtfile) from your engineering archive and flash it into the new relay. Simply copying parameter numerical setpoints will leave internal interlocking logic completely inactive. - CT Terminal Shorting Mechanics: The rear screw-terminal analog block utilizes internal spring-loaded bypass bars for CT circuits. Always inspect these terminals prior to insertion. Never pull the active electronics chassis out of its flush-mount housing while primary feeder lines are under load unless you have double-checked that external test switches (e.g., ABB FT-1 blocks) are securely isolated and shorted.
- Firmware Mismatches: If replacing a relay configured within a token-ring SPA network or older SCADA network, ensure the firmware revision suffix 07G aligns with your master polling configuration file. Altering the generation class can change database map registers, preventing the RTU from parsing event logs and trip warnings properly.
Field Engineering Note: During commissioning, ensure you verify that the CT input match parameters are calibrated for either 1 A or 5 A secondary lines. If the physical wiring comes from a 1 A secondary CT but the internal software configuration block remains defaulted to a 5 A ratio, all overcurrent protection stages will fail to trip during an active overcurrent event.
