ABB REQ615E_H protection relay Relion® product family 615 series

This is a protection relay manufactured by ABB (a global leader in power and automation technologies), specifically belonging to the renowned Relion® product family within the 615 series.

Below are the key information and features regarding the REQ615E_H:

Core Function: Differential Protection

The REQ615 series is fundamentally designed as a transformer differential protection relay.

It is primarily used to protect power transformers (especially small to medium-sized ones) by comparing the vector sum of currents on all sides of the transformer (differential current) to detect internal faults. When the differential current exceeds the set value, the relay acts quickly to trip, isolating the faulty transformer and safeguarding the power grid and equipment.

In addition to the primary differential protection function, it typically integrates a series of backup protection functions, such as:

Overcurrent protection (phase, zero-sequence/earth fault)

Overload alarm/trip

Undervoltage/Overvoltage protection

Frequency protection

Breaker failure protection

Thermal overload protection (based on IEC 60255-8 or ANSI 49)

Hardware Platform: REQ615E

REQ615E refers to the hardware platform version of this relay. ABB's relay products update their hardware platforms (denoted by suffixes like E, F, G, etc.) with technological advancements, usually signifying improvements in processing power, memory, interfaces, etc.

The H in the E_H suffix typically indicates a specific hardware configuration option or enclosure type. The precise meaning requires reference to official documentation:

It may denote a specific communication interface combination (e.g., inclusion of particular types or quantities of fiber optic/Ethernet ports).

It may denote a specific I/O (Input/Output) module configuration (e.g., number of digital inputs/outputs).

It may denote a specific power supply module option (e.g., voltage range).

Most commonly, H indicates that the device is equipped with a high sampling rate, high-accuracy analog input module (HCTs - High Core Current Transformers) for differential protection. This is a key hardware component for achieving high-performance differential protection. It is crucial for applications requiring precise current measurements, such as differential protection.

Important Note: ABB's model suffix conventions may vary slightly depending on the product line and timeframe. The most accurate sources are the device nameplate and the corresponding product manual.