Overview

The ABB RET316*4 (HESG448750M2) is a digital transformer differential protection relay engineered for medium- and high-voltage power systems. It delivers rapid and selective protection for two- or three-winding transformers, including autotransformers and generator step-up units.

This relay incorporates 87T differential, overcurrent, thermal overload, and voltage protection functions to safeguard transformers against internal faults and abnormal operating conditions. Its numerical logic, programmable I/O, and robust fault supervision help ensure grid stability and rapid fault clearance.

Designed for reliability, the RET316*4 is widely used in both utility substations and industrial distribution networks. Its compact module format makes it suitable for new installations and modernization projects with limited panel space.

Technical Data

Typical Applications

The RET316*4 is utilized for transformer and generator-transformer protection in:

• Power transmission & distribution substations

• Hydroelectric and thermal power plants

• Petrochemical and heavy industrial networks

• Renewable energy systems (wind/solar substations)

Engineers rely on it for:

• Fast internal fault clearing to prevent transformer damage

• Stable operation during inrush, energization, and external faults

• Enhanced asset integrity through thermal monitoring and trip supervision

This relay plays a key role in minimizing downtime, maintaining network reliability, and reducing catastrophic transformer failures.

FAQ

Q: What is the primary protection function?
A: High-speed 87T transformer differential protection with restraint for inrush and CT saturation.

Q: Which transformer configurations are supported?
A: Two-winding, three-winding, autotransformer, and GSU applications.

Q: Does it support control and supervision?
A: Yes — breaker control, alarm supervision, and event logging are included.

Q: Is it suitable for retrofit projects?
A: Yes — compact design and flexible mounting facilitate panel upgrades.

Q: Communication protocol?
A: Varies by relay firmware/model; serial protocols are typical in this generation.