SR745W3P5G5HIALREH Transformer Protection Relay

Description

Product Overview

The GE ​​SR745W3P5G5HIALREH​​ is a sophisticated, microprocessor-based relay engineered specifically for the complete protection and management of two-winding power transformers, a critical asset in any electrical transmission or distribution network. As a premier member of the Multilin 745 family, this device integrates a vast array of protective functions, advanced monitoring capabilities, and customizable control logic into a single, robust unit. The primary mission of the ​​SR745W3P5G5HIALREH​​ is to safeguard the transformer from internal and external electrical faults, including winding failures, through-current conditions, and system abnormalities, thereby preventing catastrophic damage and ensuring grid stability. Its integration into substation automation systems provides unparalleled visibility into transformer health and performance, enabling condition-based maintenance and maximizing asset life. The deployment of the GE ​​SR745W3P5G5HIALREH​​ is a definitive step towards achieving a resilient, efficient, and intelligent electrical infrastructure.

Technical Specifications

Main Features and Advantages

The GE ​​SR745W3P5G5HIALREH​​ stands out due to its unparalleled precision in transformer differential protection. Its core advantage is a advanced, multi-slope percentage differential characteristic with dual-harmonic restraint, which provides unparalleled security against false trips during transformer energization (inrush currents) and overexcitation conditions, while maintaining extreme sensitivity for detecting internal winding faults. The relay includes a comprehensive set of backup protection functions like time-overcurrent, instantaneous overcurrent, and thermal overload protection, creating a fully self-contained protective system.

SR745-W2-P1-G1-HI-E-H

Its advanced communication capabilities are a key feature, offering dual Ethernet ports supporting modern protocols like IEC 61850 for seamless integration into digital substations and SCADA systems. The integrated, full graphical human-machine interface (HMI) provides local access for commissioning, real-time metering of hundreds of parameters, and detailed oscillographic and event record analysis. The robust design, with a wide operating temperature range and conformally coated PCB, ensures maximum reliability in the harsh electromagnetic environment of a substation, guaranteeing continuous operation and protection of critical infrastructure.

Application Areas

The GE ​​SR745W3P5G5HIALREH​​ is the industry standard for protecting two-winding power transformers across the entire electrical value chain. Its primary application is in utility transmission and distribution substations, where it protects step-down and step-up transformers that are vital for grid integrity and voltage regulation. In the industrial sector, it is deployed to protect large furnace transformers, rectifier transformers in mining, and main plant transformers in heavy industries like metals and cement. It is also essential in generation facilities for protecting unit auxiliary transformers (UATs) that power critical station services. Furthermore, its robust protection suite makes it ideal for applications in renewable energy parks, such as wind and solar farms, where it safeguards the collector substation transformers that feed power to the grid.

Related Products

​​SR745​​ – The base product series designation.

​​SR750​​ – A feeder protection relay, often used on the downstream side of the transformer.

​​SR760​​ – A more advanced transformer protection relay for three-winding transformers with additional features.

​​SR469​​ – A motor protection relay, often protecting motors fed from the transformer.

​​UR (Universal Relay) family​​ – Such as the UR T60, another flagship transformer protection platform from GE.

​​F650​​ – A feeder management relay that could be used for backup protection.

​​ENERVISTA​​ – GE’s suite of setup and monitoring software for all Multilin relays.

Installation and Maintenance

Installation Preparation: Before installing the ​​SR745W3P5G5HIALREH​​, ensure all primary and secondary circuits are de-energized, grounded, and locked out. The installation requires meticulous planning: verify CT and VT ratios and connections match the relay’s configuration to ensure differential protection stability. The power supply must be confirmed to match the ordered specification (DC or AC). The relay is typically rack-mounted in a control panel with sufficient space for wiring and airflow. Proper grounding and segregation of analog, digital, and communication wiring is critical to prevent noise interference.

Maintenance Recommendation: Maintenance for the ​​SR745W3P5G5HIALREH​​ is heavily reliant on its advanced diagnostic and recording features. Regularly use GE’s ENERVISTA software to monitor transformer trending data (e.g., load, temperature), review event logs after system disturbances, and analyze detailed oscillographic records to verify proper operation during faults. Periodically verify the accuracy of metered values. The relay’s settings should be backed up securely. Due to its complexity, commissioning and detailed maintenance are typically performed by trained protection engineers. Keeping the firmware updated is a recommended best practice to ensure access to the latest features and security patches.