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In utility substations and industrial power houses where power transformers hum under constant load, the GE SR745-W2-P5-G5-HI-A stands guard against winding faults, inrush overloads, and ground issues that could cascade into outages. Engineers install it on two- or three-winding units from 5 MVA up, catching differential imbalances during turn-to-turn shorts or bushing failures before they escalate—think oil-filled step-up transformers feeding grid tie-ins or factory rectifiers powering arc furnaces. Steel plants rely on the GE SR745-W2-P5-G5-HI-A in industrial automation to secure phase currents up to 46x CT while tracking harmonics that signal arcing bushings, often tripping breakers faster than backup relays kick in. During commissioning of new feeders or after storm-related repairs, its metering spots hot spots via demand trends, letting ops teams derate loads preemptively. Applicable in control systems with SCADA oversight, it handles voltage sags on 120V VTs alongside Buchholz gas alarms, ensuring selective clearing in meshed networks without nuisance trips.
Field crews in renewables—wind farm collectors or solar inverters—pair the GE SR745-W2-P5-G5-HI-A with FlexLogic for custom interlocks, like blocking reclose on evolving faults detected by RTD temperature inputs. Offshore platforms value its ruggedness through humidity swings, where overcurrent curves (50/51) back up primaries while restricted earth fault elements hug neutral CTs tightly. Maintenance walks confirm health via front-panel mimic diagrams, often isolating a single phase before pulling oil samples. That blend of speed and visibility keeps transformers online longer in 24/7 grids.
The GE SR745-W2-P5-G5-HI-A is a multifunction transformer protection relay from GE Multilin’s 745 series, configured with high-range power (W2: 90-300 VDC/70-265 VAC), five programmable Form-C outputs (P5), five analog inputs (G5: 4-20/0-1 mA), high-res HMI display (HI), and Modbus RTU (A). It processes three-phase currents (1/5A CTs), ground inputs, and optional voltages via dual microprocessors, applying ANSI 87T differential, 50/51 overcurrent, 27/59 volts, and non-electrical trips like oil temp or Buchholz. In substation architectures, the GE SR745-W2-P5-G5-HI-A mounts in 19″ racks, integrating via rear RS485 or optional Ethernet for EnerVista setup and event waveforms.
Positioned for small-to-large power transformers (up to 50000A primaries), the GE SR745-W2-P5-G5-HI-A offers slope-adjusted 87 protection secure against CT saturation or magnetizing inrush, with harmonic restraint blocking false trips on energization. Integrators customize via 16 FlexLogic gates for bay control or synch-check, while metering exports kW, kvar, THD, and RTDs to SCADA. Its role excels in dual-primary setups, where split CT ratios demand precise compensation without external boxes.
Dual-core speed delivers sub-cycle 87T trips at 0.02-46x CT, with ±1.25% accuracy and frequency tracking down to 2 Hz for ride-through. Analog inputs scale oil levels or fan speeds directly into logic, while five trip-rated Form-Cs drive breakers or lockouts—each isolated to 300V. The HMI shows phasors, sequences, and event lists onsite, no laptop needed.
Casework endures –40 to +60°C vibration, IP40 dust-tight but moisture-shy, with 30 VA draw and ride-through to 16 ms. FlexCurve inverse limits and demand metering forecast aging, alerting before ANSI 49 thermal models overload.
MTBF tops 100 years via self-diagnostics and 500-event recorder (with COMTRADE), outlasting electromechanical peers in seismic zones. Operators reclose confidently via adaptive schemes, minimizing flashovers.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | GE SR745-W2-P5-G5-HI-A |
| Brand | GE Multilin 745 Transformer Protection |
| Type | Multifunction digital relay for 2/3-winding transformers |
| Control Power | 90-300 VDC / 70-265 VAC (W2 high range) |
| Phase CT Inputs | 1/5 A secondary, 1-50000 A primary, <0.2 VA burden |
| Ground CT Inputs | 1/5 A, 0.02-46x CT range |
| Analog Inputs | 5 x (4-20 mA / 0-1 mA) (G5) |
| Form-C Outputs | 5 programmable (P5) |
| Display | High-resolution LCD HMI (HI) with keyboard |
| Communication | Modbus RTU RS485 (A); optional DNP3/IEC 61850 |
| Operating Temperature | –40°C to +60°C |
| Frequency Tracking | 2-65 Hz |
| Accuracy | ±0.5% current/voltage; ±1.25% differential |
| Mounting | 19″ rack/panel |
| Weight | Approx. 8.4 kg (18.5 lb) |
| Certifications | IEEE C37.90, IEC 60255; IP40 |
- SR745-W2-P5-G5-HI-A
SR745-P2-G1-H0-A – Base model with fewer analogs, used alongside GE SR745-W2-P5-G5-HI-A for bus diff.
SR469-P5-G1-HI-A – Motor relay companion for transformer-fed drives with GE SR745-W2-P5-G5-HI-A.
T60-W2-P5-G5 – Feeder backup extending GE SR745-W2-P5-G5-HI-A selectivity.
UR Series 587T – High-end upgrade path from GE SR745-W2-P5-G5-HI-A in IEC 61850 bays.
745-W1-P1 – Low-range power variant paired with GE SR745-W2-P5-G5-HI-A redundants.
SR760 – Generator twin for plant step-ups with GE SR745-W2-P5-G5-HI-A.
C60-P5 – Capacitor bank relay integrating with GE SR745-W2-P5-G5-HI-A PF correction.
Power down bays before racking the GE SR745-W2-P5-G5-HI-A, verifying CT polarity shorts and VT fuses—reversed 87 slope trips falsely. Torque CT terminals to 25 in-lbs, route Modbus twisted-pair away from trippables, and set FlexLogic for Buchholz debounce post-commission. Baseline metering against a Fluke during tests.
Bi-annual patrols check HMI contrast and analog scaling via test pulses; dump events after faults to COMTRADE for forensics. Firmware via EnerVista during outages—archive templates per transformer ratio. Hot-swappable in drawout cases, but spares per substation beat downtime hunts.
