RET620E-1G ABB Relion Transformer Protection and Control Relay

Description

Product Model: RET620E-1G
Product Brand: ABB
Product Series: Relion 620 Series

Key Features:

• Advanced transformer protection and control for two-winding transformers
• Fully compliant with IEC 61850 and other communication standards
• Modular design with flexible configuration
• Reliable operation with comprehensive fault recording and monitoring

Applications & Industry Context

Transformers are the heart of any power system — and protecting them requires precision, intelligence, and reliability. The RET620E-1G from ABB’s Relion 620 series embodies all three. Designed specifically for two-winding power transformers and autotransformers, this Intelligent Electronic Device (IED) provides full-scale protection, control, and monitoring functions for medium- and high-voltage networks.

Across industries — from power utilities and renewable energy plants to heavy industry and petrochemical facilities — the RET620E-1G has become a trusted name. It ensures that even under severe fault conditions, transformer assets are safeguarded against internal short circuits, differential imbalances, overcurrents, and thermal stresses.

Consider a typical 110/33 kV substation where power transformers handle fluctuating loads and environmental extremes. The RET620E-1G constantly supervises current differentials between the primary and secondary windings, detecting minute deviations that could indicate insulation failure or core saturation. When such anomalies arise, the relay isolates the transformer within milliseconds — preventing catastrophic failures and ensuring service continuity for downstream consumers.

In renewable installations such as wind farms and solar substations, where transformer loading can vary dynamically, the relay’s adaptive algorithms ensure that transient currents during inverter switching do not cause nuisance tripping. Its built-in disturbance recorder captures waveform data for post-event analysis, helping maintenance teams pinpoint root causes quickly.

Mining, steel, and paper industries also rely heavily on the RET620E-1G. In such environments, transformers face mechanical vibration, temperature fluctuations, and occasional overloads. Engineers trust ABB’s robust hardware, field-proven firmware, and reliable diagnostics to maintain uninterrupted production cycles.

Product Role & System Fit

The RET620E-1G serves as a dedicated transformer protection and control IED, typically installed within the bay control cubicle of medium- or high-voltage switchgear. It’s an integral part of ABB’s Relion protection platform, sharing a common design and interface with the REF620 (feeder protection) and REM620 (motor protection) models.

Within a substation automation system, the relay performs differential protection (87T) as its primary function, comparing currents from both sides of the transformer via CT inputs. It also integrates backup overcurrent (50/51), earth-fault (50N/51N), and restricted earth-fault protection (64REF). The RET620E-1G communicates using IEC 61850, enabling seamless interaction with other IEDs, SCADA systems, and digital control systems through GOOSE messaging and MMS reporting.

Its programmable logic gives engineers flexibility to adapt the relay to specific system requirements. Control commands for circuit breakers, tap changers, or isolators can be executed directly from the IED, reducing the need for external controllers. ABB’s PCM600 configuration software provides a user-friendly environment for setting parameters, monitoring status, and analyzing recorded data.

Because the RET620E-1G belongs to the 620 Series, it shares modular hardware architecture with other Relion devices, ensuring spare parts compatibility and simplifying fleet maintenance. It’s equally suited for new installations or retrofit projects where modernization must occur without major rewiring.

Technical Specifications

Installation & Maintenance Insights

Installing the RET620E-1G is straightforward for experienced protection engineers. ABB provides standardized mounting kits for switchgear integration, and the relay’s compact design allows it to fit into existing control panels with minimal modification. During commissioning, the configuration process is supported by PCM600 templates that include typical transformer schemes — simplifying settings for differential and backup protection elements.

Cable routing is crucial: CT secondary wiring must be balanced and properly grounded to avoid false differential current readings. ABB recommends using shielded cables for communication ports to prevent electromagnetic interference. Once powered, the RET620E-1G performs an automatic self-test, confirming hardware integrity and firmware readiness before operation begins.

Maintenance is minimal. Routine inspections involve checking the health LED indicators, reviewing event logs, and verifying time synchronization. ABB advises conducting a secondary injection test annually to confirm trip characteristics. Thanks to its non-volatile memory, configuration data and recorded events are preserved even after power loss, ensuring no diagnostic information is lost.

In harsh climates, the RET620E-1G has proven resilient — with conformal-coated circuit boards that resist moisture and corrosion. Its long mean time between failures (MTBF) supports continuous operation with minimal human intervention, and firmware updates can be applied in service using ABB’s secure update protocol.

Technical Features & Benefits

The RET620E-1G stands out for its combination of sophisticated functionality and practical usability. Its differential protection algorithm employs advanced restraint and bias characteristics, enabling accurate fault discrimination even under high magnetizing inrush or CT saturation conditions.

The relay’s thermal overload protection continuously monitors winding temperature through current-based models, providing timely alarms before overheating becomes critical. When combined with tap changer control, it enables optimal transformer loading while preserving insulation life.

From a system integration perspective, the RET620E-1G supports redundant Ethernet communication (PRP/HSR) — ensuring zero packet loss in case of link or device failure. It’s compatible with ABB’s 800xA and MicroSCADA Pro systems, but it also works seamlessly with other vendors’ SCADA platforms through DNP3 or Modbus.

The intuitive HMI provides real-time visualization of transformer status, including phase currents, voltage levels, and breaker positions. Engineers can quickly issue local control commands, review disturbance records, or reset protection trips without needing a laptop.

ABB’s Relion firmware platform ensures consistent menu structures and configuration logic across the product family, simplifying cross-training and reducing engineering time. For utilities managing multiple substations, this commonality is invaluable — allowing technicians to move between sites without retraining.

A further benefit is its built-in disturbance recorder, capturing oscillographic data at high resolution during fault events. These recordings, exportable in COMTRADE format, are essential for post-fault analysis and system optimization. With the RET620E-1G, ABB delivers not only protection but also powerful insight into network behavior.

Related Models

• RET615 – Compact transformer protection relay for single two-winding units
• RET620 – Base model with extended function sets; variant of RET620E-1G
• REF620 – Feeder protection and control IED, same communication platform
• REM620 – Motor protection IED for industrial applications
• REB500 – Centralized busbar protection system for multi-feeder substations
• REG615 – Generator and interconnection protection relay
• REC615 – Bay control and supervision unit for switchgear automation