Application Scenarios
A large industrial substation experienced frequent differential protection misoperations on its main transformer shortly after commissioning, causing unplanned outages. The maintenance team traced the root cause to a ratio mismatch between the CTs on different sides of the transformer. The station had selected the GE 745-W3-P511-G51-HI-R-E, which includes dynamic CT ratio mismatch compensation capable of automatically correcting the unbalanced current caused by differing CT ratios. After the technicians recalibrated the protection settings through the EnerVista 745 software, the differential misoperations were eliminated and the transformer returned to stable operation. This case highlights the GE 745-W3-P511-G51-HI-R-E’s adaptability in mixed CT ratio scenarios and the advantages of its digital protection algorithms over traditional electromechanical relays.
Parameter
| Parameter | Value/Description |
|---|---|
| Product Model | GE 745-W3-P511-G51-HI-R-E |
| Manufacturer | GE Multilin (GE Grid Solutions / GE Vernova) |
| Product Category | Transformer Management Relay (Numerical Protection Relay) |
| Winding Configuration | W3 — Three windings per phase |
| Phase CT Inputs (P511) | W1: 5 A; W2: 1 A; W3: 1 A (mixed configuration) |
| Ground CT Inputs (G51) | W1/W2: 5 A; W2/W3: 1 A |
| Control Power (HI) | 90–300 V DC; 70–265 V AC at 48–62 Hz |
| Display | Enhanced 40-character backlit LCD |
| Restricted Ground Fault (R) | Enabled — zero-sequence differential for sensitive ground fault detection |
| Logic Inputs | 16 (dry/wet contact) |
| Output Relays | 8 (1 solid-state + 4 Form-A trip-rated + 4 Form-C auxiliary) |
| Communication Protocols | Modbus RTU, Modbus TCP/IP, DNP 3.0 Level 2 |
| Operating Temperature | −40 °C to +60 °C |
| Lifecycle Status | Discontinued — migration path to Multilin 845 relay |
