ABB REF601 Feeder Protection Relay – Reliable overcurrent and earth-fault protection for MV distribution feeders

The ABB REF601 is a compact numeric feeder protection relay designed for medium-voltage distribution feeders in secondary substations and industrial switchgear. It focuses on non-directional overcurrent and earth-fault protection, trip logic, basic control, and status indication. From my experience, it’s a solid choice when you want dependable protection without the complexity of a full substation IED platform. You might notice that it fits particularly well in ring-main units and compact switchgear where space and simplicity matter.

Our Order Placement Process and Guarantees

• Warranty: 365 days from delivery
• Delivery: 1 week if in stock; no more than 1 month latest
• Payment: 50% advance payment; full payment before delivery
• Express options: FedEx, UPS, DHL
• Order support: technical cross-check of part codes and I/O needs before we ship

Key Features

• Non-directional overcurrent (50/51) and earth-fault (50N/51N) – Core protection for MV feeders, typically set up with separate definite/IDMT curves.
• Selectable CT inputs (1 A / 5 A) – Suits existing CT circuits; minimizes retrofit work.
• Trip logic and interlocks – Basic logic elements to coordinate trips, lockout, and breaker control in many cases.
• Event and fault recording – Time-stamped events help with disturbance analysis and faster restoration.
• Local HMI with LEDs – Clear indication of pickup, trip, and relay health; operators typically find it easy to interpret.
• Self-supervision – The relay monitors its own health and signals any internal fault, which reduces blind failures.
• Communication (variant-dependent) – Modbus RTU / IEC 60870-5-103 via RS‑485 are commonly available; some variants support Ethernet/IEC 61850.
• Compact flush-mount design – Fits space-constrained switchgear doors and RMUs; wiring is straightforward.

Technical Specifications

Related or Supporting Products

• ABB REF615 – More advanced feeder protection with wider function set and IEC 61850 as standard on many variants; good when you need directional EF, synchrocheck, or larger I/O.
• ABB REF610 – Earlier-generation feeder protection; REF601 typically offers a more compact footprint and updated electronics.
• ABB REM601 – Motor protection relay in the same family; a suitable companion when feeders supply large MV motors.
• ABB REF630/620 – For complex schemes requiring advanced logic, bay control, or extensive GOOSE messaging.
• ABB RTXP 18 test switch – Useful accessory for safe secondary injection testing and isolation during maintenance.
• Current transformers (1 A / 5 A) – Match CT ratio and accuracy class to protection settings for best discrimination.

Installation & Maintenance

• Panel and environment – Mount on a rigid switchgear/panel door with sufficient ventilation. Avoid direct sun and condensation; keep ambient within the specified temperature range.
• Wiring practices – Route CT leads twisted and shielded where practical; ground shields at one end. Verify polarity (P1/P2, S1/S2). Use separate returns for trip and auxiliary circuits to reduce interference.
• Commissioning – Perform secondary injection to verify 50/51 and 50N/51N curves, pickup, and timing. Check trip circuit supervision and interlocks. Back up settings after validation.
• Protection coordination – In many cases, pairing IDMT curves with upstream/downstream devices gives cleaner selectivity; review cold-load pickup and inrush behavior.
• Routine maintenance – Dust the HMI and terminals periodically; tighten control wiring per torque specs. Re-verify settings annually or after network changes. Keep firmware up to date where applicable.
• Safety – Apply lockout/tagout. Short CT secondaries before disconnection. Confirm zero energy on trip circuits before service.

Quality & Certifications

• CE marked; designed to comply with relevant IEC protection standards for MV applications
• RoHS compliant materials; manufactured under ISO 9001 quality systems
• Many variants evaluated for use in North America (UL/cUL) – check exact order code for listing
• Manufacturer’s standard warranty is supported by our 365-day coverage