ABB REF620 (Relion 620 series) feeder protection and measurement device

6. Communication abnormality. If the backend communication is interrupted, first check the physical layer: network cable/fiber optic cable, switch port, communication module indicator light; Recheck the link layer: IP address, subnet VLAN； Finally, check the application layer: IEC 61850 dataset, GOOSE subscription, Modbus register mapping. For PRP/HSR, the dual network configuration and redundant box status should be confirmed.

7. Unable to reset after protective action. Check the trip hold, circuit breaker mechanism, auxiliary contacts, closing interlock, and reclosing logic. If the protection has been reset but the circuit breaker cannot be closed, the control circuit and interlocking conditions should be checked instead of repeatedly pressing the closing button.

Replacement and maintenance suggestions

When replacing REF620 or using it for old cabinet renovation, it is recommended to establish a "four-dimensional checklist": mechanical dimensions and installation methods, electrical input and output and CT/VT/sensor types, communication protocols and redundancy methods, ordering codes and certification documents. REF620 supports flush, semi flush, rack mounted, wall mounted, and 19 inch installation. The panel opening size is 162 ± 1mm high and 248 ± 1mm wide. Before replacing, the old device opening, terminal height, and depth should be measured to confirm the space inside the cabinet.

When migrating parameters, do not only migrate protection settings. Control logic, GOOSE configuration, LED mapping, event recording settings, and communication parameters should be migrated simultaneously. Before operation, secondary injection test, trip transmission, interlock test, point-to-point communication test, and background signal verification should be completed. During the maintenance cycle, self inspection records, trip circuit monitoring status, event records, and load curves should be regularly checked, and maintenance should be arranged based on the number of circuit breaker actions and fault current levels.

The reliability of REF620 is based on correct selection, wiring, and configuration. If on-site engineers can string "hardware verification - protection setting - communication networking - fault record analysis" into a closed loop, it can significantly shorten power outage time in feeder protection modification, fault investigation, and daily operation and maintenance, and improve the observability and maintainability of the distribution system.