GE Multilin 745-W2-WP5-G5-HI Transformer Protection Relay

Product Description

745-W2-WP5-G5-HI is a digital transformer protection relay from GE Multilin, part of GE Grid Solutions, engineered specifically for the protection of two-winding power transformers. The relay combines fast differential protection with supplemental electrical safeguards to detect internal faults, abnormal operating conditions, and system disturbances before equipment damage occurs.

Built on a microprocessor-based platform, this relay continuously evaluates current and voltage inputs to provide accurate fault discrimination. Advanced algorithms, including adaptive harmonic restraint and current transformer ratio compensation, improve stability during inrush events and commissioning conditions where CT mismatches may exist. The compact hardware design supports integration into modern substation panels while maintaining the performance required for medium- and large-scale transformer assets.

Protection and Control Functions

The relay delivers a coordinated protection scheme designed for transformer applications:
Percent differential protection for internal fault detection
Time and instantaneous overcurrent protection
Frequency supervision for abnormal system conditions
Overexcitation (V/Hz) protection to prevent core saturation and thermal stress
Adaptive harmonic blocking to maintain security during energization

Technical Specifications

Model: 745-W2-WP5-G5-HI
Manufacturer: GE Multilin (GE Grid Solutions)
Supported Transformer Configuration: Two-winding transformers
Measurement Inputs: Phase currents and voltages via external CTs and VTs
Differential Algorithm: Percentage-based with adaptive restraint
CT Ratio Compensation: Automatic correction for ratio mismatch
Operating Temperature Range: –40 °C to +60 °C
Storage Temperature Range: –40 °C to +80 °C
Humidity Rating: Up to 90 percent, non-condensing
Communications: Multi-protocol support for substation automation and SCADA systems

Typical Applications

This relay is commonly deployed in:
Utility substations protecting distribution and transmission transformers
Industrial power systems with dedicated step-up or step-down transformers
Energy infrastructure where high-speed fault isolation is required
Retrofit projects replacing legacy electromechanical differential relays

Model Comparison Note

Within the GE Multilin 745 family, the W2 configuration is optimized for two-winding transformer protection. Other variants in the series may support additional windings or extended control functions, but the 745-W2-WP5-G5-HI focuses on high-speed, secure protection without unnecessary complexity.

FAQ

Q: Is this relay suitable for three-winding transformers?
A: No. This model is specifically designed for two-winding transformer configurations. Three-winding applications require a different relay variant.

Q: How does harmonic restraint improve reliability?
A: The relay dynamically analyzes harmonic content during transformer energization to prevent false differential trips caused by magnetizing inrush currents.

Q: Can the relay compensate for CT ratio errors?
A: Yes. Built-in CT ratio mismatch correction improves measurement accuracy during commissioning and retrofit installations.