Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 745-W3-P5-G5-HI-A-L-R-E-H |
| Manufacturer | GE Multilin (GE Vernova / GE Grid Solutions) |
| Product Type | Transformer Management Relay / Numerical Transformer Protection IED |
| Series / Platform | Multilin 745 Transformer Protection System (SR745) |
| Winding Configuration | W3 — three windings per phase (three-winding transformer, autotransformer, reactor) |
| Phase Current Inputs | P5 — 5 A nominal CT secondary, nine phase current inputs (three per winding) |
| Ground Current Inputs | G5 — 5 A nominal CT secondary, ground / neutral / sensitive ground channels |
| Control Power | HI — 90 to 300 V DC or 70 to 265 V AC, 48 to 62 Hz |
| Current Withstand | 80× rated current for 1 second; 3× rated current continuous; CT burden < 0.2 VA |
| Voltage Input | 60 to 120 V AC VT secondary, burden < 0.025 VA, source VT range 2 to 600 kV |
| Digital I/O | 16 programmable logic inputs (wet/dry); 8 output relays |
| Analog I/O (A option) | 4 analog inputs and 8 analog outputs, 0 to 1 mA / 0 to 20 mA / 4 to 20 mA |
| RTD Inputs | 3-wire, 100 Ω Platinum (DIN 43760), 100 Ω Nickel, 120 Ω Nickel; IRIG-B time sync input |
| Protection Functions | 87T dual-slope percentage differential with 2nd and 5th harmonic restraint, 87TG / 64REF restricted ground fault, 50/51P, 50/51N, 50G/51G, 46, 24 V/Hz overexcitation, 81U/81O, df/dt, 49 thermal |
| Differential Trip Time | Typically less than 30 ms for internal winding faults |
| Recording Capability | 64 samples per power cycle; 128 time-stamped event records; 16 cycles of oscillography; THD to the 21st harmonic |
| Communication Interfaces | Front RS232, two rear RS485/RS422 selectable ports; Modbus RTU and DNP 3.0 Level 2, 300 to 19200 bps (10Base-T Ethernet is a separate factory option on other 745 builds) |
| Display / HMI | E — enhanced 40-character backlit LCD with membrane keypad and 22 status LEDs |
| Operating Environment | -40 °C to +60 °C operating; -40 °C to +80 °C storage; 5 to 95 % RH non-condensing; Pollution Degree II; up to 2000 m altitude |
| Enclosure / Coating | IP40 front, IP20 rear; H — harsh-environment conformal coating fitted |
| Dimensions (H × W × D) | 229 × 178 × 184 mm (9 in × 7 in × 7 1/8 in) |
| Weight | Approximately 4.8 kg for the relay module; approximately 8.4 kg with the draw-out case |
| Mounting | Flush panel or 19-inch rack, draw-out case with automatic CT shorting |
| Configuration Software | EnerVista 745 Setup software (part of the EnerVista suite) |
| Compliance | IEC 60255, IEEE C37.90, ANSI, UL/cUL listed, CE marked |
| Lifecycle Status | Legacy platform; GE recommends the Multilin 845 for new designs |
Main Features and Advantages
Dual-slope percentage differential protection with adaptive harmonic restraint: The core strength of the 745-W3-P5-G5-HI-A-L-R-E-H is its variable dual-slope percentage differential element, which maintains stability during heavy through-faults and CT saturation while remaining highly sensitive to low-level internal winding faults. Second-harmonic blocking prevents nuisance tripping during transformer energization inrush, and fifth-harmonic blocking supervises overexcitation conditions, while GE’s adaptive algorithms — dynamic CT ratio mismatch correction and adaptive harmonic restraint — continuously compensate for ratio errors, tap position changes and CT saturation so that security and dependability are preserved without desensitizing the element.
Restricted ground fault and transformer life management: Fitted with both the R and L options, the 745-W3-P5-G5-HI-A-L-R-E-H adds high-sensitivity restricted ground fault protection for winding-to-ground faults close to the neutral point, a fault region that plain differential elements often cannot see, and simultaneously calculates hottest-spot temperature, aging factor and cumulative loss of life. This turns the relay from a pure protection device into an asset management tool, letting operators decide when to shed load, when to defer a capital replacement and whether a planned outage is economically justified.
Integrated analog I/O, FlexLogic and metering: With the A option, the 745-W3-P5-G5-HI-A-L-R-E-H provides analog transducer inputs and multiple 4 to 20 mA outputs so that transformer loading, winding temperature and demand values can be hardwired to chart recorders, PLCs or SCADA without protocol polling. FlexLogic programmable logic implements custom interlocks, breaker failure schemes, tap-changer supervision and alarm matrices internally, removing rows of auxiliary relays and wiring. Built-in metering covers current, voltage, power, energy, power factor, frequency and harmonic distortion, eliminating separate transducers and their associated panel space and calibration burden.
Engineered for availability and harsh service: The conformal coating specified by the H suffix protects the internal electronics against humidity, salt-laden air and industrial chemical atmospheres, while the -40 °C to +60 °C rating and high EMC immunity suit unheated substation kiosks and switchgear rooms alike. The draw-out case with automatic CT shorting means the 745-W3-P5-G5-HI-A-L-R-E-H can be withdrawn, tested or replaced without opening a live CT circuit and without de-energizing the whole bay, which dramatically reduces maintenance outage duration. Comprehensive self-diagnostics, a security audit trail for setting changes and the built-in waveform playback simulation mode, which allows setpoint verification against recorded or computer-generated waveforms before commissioning, complete a package that minimizes both nuisance trips and unplanned downtime.
