ABB RET620 – Transformer protection and control relay for 2- or 3‑winding power transformers

The ABB RET620 is a Relion 620‑series protection and control IED designed specifically for power transformers. From my experience, it’s a solid fit for utilities, IPPs, and industrial substations that want dependable transformer differential protection with modern IEC 61850 communications and straightforward HMI. One thing I appreciate is how it handles multi‑winding configurations and adds practical extras like disturbance recording and flexible logic without turning commissioning into a science project.

Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery time: 1 week if in stock; no more than 1 month at the latest
• Payment: 50% advance payment; full payment prior to delivery
• Express options: FedEx, UPS, DHL

You might notice that orders go faster when we receive the variant code and desired communication options upfront (for example Ethernet + IEC 61850, or serial + Modbus). That typically shortens configuration and testing on our side.

Key Features

• Transformer differential (87T) – Sensitive and fast protection for 2‑ or 3‑winding transformers with stabilized algorithms to ride through inrush and CT errors.
• Restricted earth fault (64REF) – High‑sensitivity protection for internal ground faults, in many cases enabling faster clearance than plain overcurrent.
• Backup protections – Phase/earth overcurrent (50/51/50N/51N), thermal overload (49), over/under‑voltage (59/27), frequency (81), and breaker failure (50BF) to cover most feeder/transformer contingencies.
• Flexible I/O and logic – Configurable binary I/O and IEC 61131‑style logic blocks streamline interlocking and scheme logic without extra hardwiring.
• IEC 61850 with GOOSE – Fast peer‑to‑peer messaging for trip and interlocking; seems to be the preferred route for reducing copper wiring in new builds.
• Disturbance and event records – COMTRADE disturbance files and detailed event logs make fault analysis faster and more transparent for O&M teams.
• Intuitive HMI – Front panel with clear single‑line views and LEDs; operators typically find status checks and manual controls effortless.
• Cybersecurity basics covered – Role‑based access, password protection, and audit trails align with common utility requirements.
• PCM600 engineering tool – Parameterization, logic, and IED management through ABB’s PCM600 keep lifecycle work consistent across Relion devices.

Technical Specifications

Where it typically fits

– 110/132 kV and 220/230 kV substations protecting primary transformers with IEC 61850 station bus.

– Industrial plants (steel, mining, oil & gas) where transformer differential plus robust backup protection is needed on limited space.

A utility client recently swapped aging electromechanical relays for RET620 on a 50 MVA transformer. Fault event retrieval through COMTRADE shortened their root‑cause analysis from days to hours, which, in many cases, is what decides whether you miss a production target or not.

Related or Supporting Products

• ABB RET615 – Compact transformer protection for two‑winding units; good when space is tight and the scheme is simpler.
• ABB RET630 – More advanced transformer protection with extended I/O and application flexibility for complex schemes.
• ABB REF620 – Feeder protection; a suitable companion on the HV/LV sides if you standardize on Relion 620.
• ABB REM620 – Motor protection; useful in the same substation when large MV motors share the process bus.
• ABB RTXP 24 test switch – Test switch accessory to safely isolate and test circuits during commissioning and maintenance.
• ABB COM600E – Substation gateway/HMI for IEC 61850 systems if you are building a unified station‑level architecture.

Installation & Maintenance

• Panel and environment – Mount in a clean, ventilated cabinet per IEC 62271 norms; keep ambient within the stated temperature range and below ~95% RH non‑condensing.
• Wiring – Use proper CT/VT polarity and earthing practices; segregate power and signal wiring; for Ethernet, use Cat5e/Cat6 shielded where required.
• Commissioning – Parameterize with PCM600, verify ratio/phase compensation and slope settings for 87T, run secondary injection tests, and validate GOOSE subscriptions if used.
• Safety – Prove dead, short CT secondaries before disconnection, and follow lockout/tagout. Arc‑safe procedures are recommended during live system tests.
• Routine maintenance – Review event logs quarterly, export disturbance records after trips, clean the HMI and ventilation paths, and back up configuration. Firmware updates can be applied during planned outages after compatibility checks.
• Spares – Keeping a spare HMI and a pre‑configured IED on the shelf can cut mean time to restore in many cases.

Quality & Certifications

• CE‑marked; tested to relevant IEC 60255 standards for protective relays.
• Produced under ISO 9001 quality management.
• RoHS compliant; UL/cUL listings apply to many variants (availability can be variant‑specific).
• IEC 61850 conformance tested; supports GOOSE messaging for station bus applications.

Manufacturer warranty terms apply per ABB policy; our supply is backed by a 365‑day warranty as stated above.