Description
GE Multilin 745-W2-P5-G5-HI
Product Introduction
Transformer protection problems are unforgiving: a relay that has the correct series number but the wrong CT input or control-power configuration can become a commissioning problem very quickly. The GE Multilin 745-W2-P5-G5-HI is a transformer protection and management relay configured for two windings per phase, with 5 A phase-current and 5 A ground-current inputs. Its high-range control-power supply accepts 90–300 VDC or 70–265 VAC at 48–62 Hz.
This configuration is suited to established transformer protection panels where the original 745 architecture must be maintained rather than redesigned. The relay provides protection functions, metering, monitoring, and programmable control logic within the 745 platform. When sourcing a replacement, do not stop at “745 relay”—the W2, P5, G5, and HI order-code segments directly affect the electrical interface. Variants with suffixes such as -A, -E, or -R-T can add different hardware or functional options and should not be assumed interchangeable.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | 745-W2-P5-G5-HI |
| Manufacturer | GE Multilin |
| Product Family | Multilin 745 Transformer Protection System |
| Product Type | Transformer protection / management relay |
| Transformer Configuration | Two windings per phase |
| Phase Current Input | 5 A |
| Ground Current Input | 5 A |
| Control Power, DC | 90–300 VDC |
| Control Power, AC | 70–265 VAC |
| AC Frequency | 48–62 Hz |
| Voltage Relay Input | 60–120 V |
| Operating Temperature | -40 to +60°C |
| Storage Temperature | -40 to +80°C |
| Operating Humidity | Up to 90% non-condensing |
| Display | 40-character LCD |
| Communication | RS-232; RS-485/RS-422 depending on hardware/configuration |
| Protocol | Modbus RTU supported |
| Enclosure / Chassis | SR-series draw-out relay with companion case |
| Approx. Dimensions | 9 in H × 7 in W × 7⅛ in D |
| Approx. Weight | 4.8 kg |
| Software Environment | EnerVista 745 |
The published specifications consistently identify the high-range control-power configuration and 5 A CT inputs. Exact communication hardware should be verified against the physical rear terminal arrangement because the 745 family was offered with different option combinations.
Application Scenarios & Pain Points
A transformer relay replacement usually happens under less-than-ideal conditions: the transformer is already in service, the protection panel has years of wiring history, and the original relay configuration may be difficult to reconstruct. The 745-W2-P5-G5-HI is most relevant where the existing protection scheme was engineered around the GE Multilin 745 platform.
- Two-winding power transformers: The W2 configuration is intended for applications with two windings per phase.
- Transformer differential protection: The 745 platform supports transformer protection functions used to identify internal faults and abnormal operating conditions.
- Ground-fault protection: The G5 configuration provides 5 A ground-current input capability for compatible CT circuits.
- Transformer monitoring and management: Metering, operating data, alarms, and programmable logic can be integrated into the protection scheme.
- Legacy protection-panel replacement: Useful when maintaining an existing 745-based installation is more practical than replacing the entire protection architecture.
Field note: Before removing an existing relay, record CT ratios, polarity, phase identification, trip logic, auxiliary contacts, control power, communications wiring, and all active settings. A replacement with the same family name can still have materially different hardware options.
745-W2-P5-G5-HI
Related Products
- GE Multilin 745-W2-P5-G5-HI-A — Adds analog input/output functionality compared with the base configuration.
- GE Multilin 745-W2-P5-G5-HI-A-E — Adds the enhanced-display option to the A configuration.
- GE Multilin 745-W2-P5-G5-HI-A-E-H — Extended configuration with analog I/O, enhanced display, and additional options.
- GE Multilin 745-W2-P5-G5-HI-R-T — Related W2/P5/G5/HI configuration with additional option coding; verify the complete suffix before substitution.
- GE Multilin 745-W2-P15-G1-LO-A-R — Two-winding 745 configuration with different current-input and control-power coding.
- GE Multilin 745-W3-P5-G5-HI-A — Three-winding counterpart; not a direct replacement for the W2 configuration.
- GE Multilin 745-W3-P5-G5-HI-A-E — Three-winding configuration with enhanced option set.
- GE Multilin 745-W3-P5-G5-HI-R-E — Another W3 configuration with different option coding.
The important distinction is not simply W2 versus W3. The P, G, HI/LO, and suffix options define the electrical and functional configuration, so a complete order-code comparison is required before substitution.
Engineer’s Guide — Field Pitfalls to Avoid
Pitfall 1: Buying a 745 with the wrong CT configuration
The P5 and G5 portions of the order code matter. The base model is configured for 5 A phase and 5 A ground-current inputs. A relay with a different CT option is not automatically interchangeable.
Avoidance: Match every CT input rating and transformer winding configuration against the protection drawings before purchase.
Pitfall 2: Confusing HI and LO control-power versions
The HI version accepts approximately 90–300 VDC or 70–265 VAC, while published documentation for LO configurations shows a substantially lower control-power range.
Avoidance: Measure the actual panel control voltage and compare it with the complete relay order code. Do not rely on the cabinet’s nominal voltage label alone.
Pitfall 3: Assuming the base model has every optional feature
The 745 family contains configurations with analog I/O, enhanced displays, restricted ground-fault functions, communications options, and other hardware differences. For example, the 745-W2-P5-G5-HI-A-E is not equivalent to the base HI configuration simply because the first part of the number matches.
Avoidance: Compare the complete order code, rear terminals, and installed option cards.
Pitfall 4: Ignoring the case and mounting arrangement
The 745 is a draw-out relay design. Some procurement records refer to the relay unit separately from its companion case.
Avoidance: Confirm whether the replacement requirement is for the relay module only or the complete relay-and-case assembly.
Pitfall 5: Treating stored settings as interchangeable with the hardware
Protection settings are only meaningful when the hardware configuration supports the corresponding inputs and functions.
Avoidance: Export and archive the existing settings before replacement, then verify CT scaling, phase compensation, trip logic, communication parameters, and enabled protection elements during commissioning.
FAQ
What is the GE Multilin 745-W2-P5-G5-HI?
It is a GE Multilin 745 transformer protection and management relay configured for two windings per phase. The P5 and G5 codes correspond to 5 A phase and ground-current inputs, while HI identifies the high-range control-power configuration.
What control voltage does the 745-W2-P5-G5-HI require?
The high-range version is documented for approximately 90–300 VDC or 70–265 VAC at 48–62 Hz. Verify the actual panel supply before installation.
Is the 745-W2-P5-G5-HI suitable for a three-winding transformer?
Not as a direct assumption. W2 identifies a two-winding-per-phase configuration, while 745 models beginning with W3 are designed around three-winding applications.
Does 745-W2-P5-G5-HI have 5 A CT inputs?
Yes. The P5 configuration identifies 5 A phase-current inputs, while G5 identifies 5 A ground-current input capability.
Is 745-W2-P5-G5-HI the same as 745-W2-P5-G5-HI-A?
No. The -A suffix identifies an additional option configuration. Available technical records describe the A version as including analog input/output functionality.
What software is used with the 745 relay?
The 745 family is associated with EnerVista 745 configuration and monitoring software. Before replacing a relay, save the existing configuration and confirm that the replacement hardware supports the functions used by the installed settings.
What should procurement verify when sourcing this relay?
Request the complete 745-W2-P5-G5-HI order code, nameplate photographs, hardware/revision information, relay-versus-case configuration, CT input ratings, control-power range, communications hardware, and actual inventory condition. For a protection relay, matching the complete configuration is much safer than purchasing by the “745” family number alone.
