Description
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BrandABB
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ModelREX521GHHPSH08G
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Product NameNumerical Feeder Protection and Control Relay
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Dimensions148.8 mm width, 265.9 mm frame height, 249.8 mm case height, 235 mm depth
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Weight4.8 kg
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Place of OriginFinland
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HS Code85364900
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Operating Temperature‑25 ℃ to +55 ℃
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Storage Temperature‑40 ℃ to +85 ℃
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Power Supply100 V‑120 V
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Warranty12 month
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Statusnew and original
REX521GHHPSH08G belongs to ABB REX521 protection relay family, widely deployed for medium-voltage feeders, medium-large AC motors and backup transformer protection. It handles various neutral-earthing network types and provides reliable fault recording for post-event analysis.
Fault-Diagnosis Procedures for ABB REX521GHHPSH08G
Visual indicator inspection: Check the status of READY, START, TRIP and IRF LEDs. A steady READY LED signifies normal operating status; flashing READY LED means the unit is under test mode; latched TRIP LED indicates a protection-initiated trip event; IRF alarm points to internal hardware failure. Document all LED statuses prior to further troubleshooting;
Self-supervision and internal fault check: Retrieve internal diagnostic codes through front-panel HMI or CAP505 configuration tool. Check alarms including FLASH memory fault, EEPROM fault, RAM fault, hardware module malfunction and auxiliary power supervision alarm. Confirm firmware version integrity. Clear temporary alarms after eliminating root causes. Perform power-cycle operation for troubleshooting intermittent internal faults;
Wiring and auxiliary power inspection: Measure auxiliary supply voltage to comply with device rated specifications. Check terminal torque, CT/VT secondary wiring, digital I/O wiring and communication cables. Assess risks of CT secondary open-circuit, PT fuse failure and protective earthing performance. Examine cable insulation condition and connector oxidation;
Fault event and disturbance record analysis: Access event logs, fault records and disturbance recorder files. Capture fault timestamp, fault category, pick-up parameters, phase current/voltage magnitudes and operation sequence. Differentiate real primary-system faults, nuisance tripping induced by wiring defects and incorrect parameter settings;
Analog input channel diagnosis: Inject secondary test signals, compare applied current/voltage values against measured readings on the relay. Verify phase sequence, signal polarity, measurement overflow and signal drift. Locate CT/PT open-circuit, short-circuit and reversed-wiring failures;
Digital I/O fault diagnosis: Enable test mode via HMI menu. Activate each digital input externally and validate corresponding status feedback. Actuate relay outputs (SO, PO, HSPO) within test mode to confirm contact switching performance. Inspect contact burnout, cable breakage and dry-contact compatibility. Validate trip-circuit supervision function;
Protection logic and parameter verification: Review protection thresholds, time delays, interlock logic and signal mapping configurations. Confirm full parameter download completion. Identify improper settings resulting in mal-operation or failure-to-operate. Simulate fault scenarios to verify protection element pick-up and output response;
Communication fault diagnosis: Inspect physical connections for SPA-BUS, LON and RS485 interfaces. Verify baud rate, device address and protocol setup. Validate data interaction with SCADA system over IEC60870-5-103, Modbus and DNP3. Troubleshoot communication timeout, frame error and offline failures. Reset communication ports when required;
Fault reset and function validation: Manually reset latched TRIP indication via front keypad or software tool. Clear historical event logs while preserving disturbance recorder data. Exit test mode. Conduct comprehensive functional tests after fault rectification. Confirm zero active alarms and restore the relay to normal online operation;
Final documentation: Record fault codes, phenomenon descriptions, root-cause analysis and corrective measures. Create backup copies of full parameter configuration and disturbance record files.
Wiring Instructions for ABB REX521GHHPSH08G
CT Secondary Wiring: Connect three-phase current transformers and residual current transformers to the analog current input terminals of the relay. The device supports configurable 1A/5A rated secondary current. Ensure correct wiring polarity and phase sequence during connection. Short-circuit CT secondary loops in advance before any wiring operation, and strictly prohibit open-circuit operation of CT secondary circuits to avoid high-voltage hazards.
VT Secondary Wiring: Connect three-phase voltage transformers and residual voltage transformers to the device’s voltage input terminals with a rated secondary voltage of 100V. Verify accurate phase sequence and wiring polarity. Install protective fuses on the VT secondary side, and strictly prevent short-circuit faults in VT secondary circuits to ensure stable voltage sampling.
Digital Input Wiring: The optically isolated digital inputs support 24–250V AC/DC power supply and are compatible with dry contact signals. Connect on-site status contacts, circuit breaker auxiliary contacts and electrical interlock signal contacts to corresponding digital input terminals. Unify the reference potential of all digital input loops for stable signal acquisition.
Relay Output Wiring: The high-speed power output (HSPO) is dedicated to the main breaker trip circuit, supporting single-pole and double-pole wiring modes for tripping control. Power outputs (PO) are applied for circuit breaker and disconnector operational control. Signal outputs (SO) are used for on-site fault and alarm indication. The IRF output realizes remote signalization of device internal faults. The trip circuit supervision (TCS) circuit is wired for real-time monitoring of the trip loop integrity. All relay contacts are rated at 250VAC / 30VDC, with NO/NC contacts selectable according to on-site logic design requirements.
Auxiliary Power Supply Wiring: Access the auxiliary power supply to the dedicated power input terminals, with a applicable voltage range of 110–240VAC / 110–250VDC. AC power wiring has no polarity restriction, while DC power wiring must strictly follow positive and negative polarity specifications. Connect the device protective earth terminal to the cabinet safety ground via low-impedance grounding cables to meet safety grounding standards.
Communication Wiring: The SPA-BUS optical interface is used for local connection and parameter configuration via dedicated tools. The RS485 differential communication bus adopts shielded twisted-pair cables, with strictly distinguished DATA A and DATA B terminals to avoid reverse connection. Implement single-end shielding grounding at the cabinet side, and install terminal resistors at the physical end of the bus. The device supports multiple communication protocols including LON, IEC60870-5-103, Modbus and DNP3 for data transmission with upper monitoring systems.
General Wiring Specifications: Classify and lay cables separately for high-power secondary circuits, analog measurement circuits and communication signal cables, and avoid long-distance parallel laying to prevent signal interference. Fasten all terminals in accordance with the standard torque requirements. Conduct a comprehensive wiring inspection before power-on, and confirm that all circuits are free of short-circuit, open-circuit and mis-wiring faults.
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