GE SR745‑W3‑P5‑G5‑HI Transformer Management Relay

Technical Specifications

Model: SR745‑W3‑P5‑G5‑HI

Brand: GE Multilin (GE Vernova)

Product Type: Digital Transformer Management Protection Relay

Applicable System: Three‑winding power transformer, autotransformer protection system(W3)

CT Secondary Input: 5A phase current transformer input(P5)

Ground CT Input: 5A multi‑range ground fault current input(G5)

Control Power: 70‑265VAC / 90‑300VDC universal high‑range power supply(HI), 48‑62Hz

Display: 40‑character multi‑line LCD liquid‑crystal display with operation keypad

Voltage Input: Three‑phase VT voltage sampling input, burden＜0.025VA@120V

Temperature Sensor: Support 3‑wire RTD Pt100, Ni100, Ni120 winding‑oil temperature detection

Communication Interface: Front‑panel RS232 local programming port, rear RS485 Modbus RTU communication port

Mounting Mode: Panel flush mounting, standard 19‑inch panel installation

Front‑panel Protection Grade: IP40

Digital Input: 16‑channel opto‑isolated programmable digital input

Relay Output: Multi‑group programmable trip & alarm relay outputs, breaker trip contact rating 15A

Recording Function: Event log, fault waveform capture, disturbance record, transformer thermal loss‑of‑life record

Logic Function: FlexLogic flexible programmable logic, adaptive CT mismatch correction, harmonic restraint algorithm

Power Consumption: Typical 32VA

Operating Temperature:‑40℃ ~ +60℃, non‑condensing

Humidity:5%‑95% non‑condensing

Weight:4.8kg

Dimension:228mm ×178mm ×114mm

Application: Power‑plant three‑winding main‑transformer, substation three‑winding power transformer, large‑capacity industrial transformer, autotransformer comprehensive protection

Product Function Description

SR745‑W3‑P5‑G5‑HI belongs to GE Multilin 745 series transformer management relay, which is specially designed for three‑winding power transformers and autotransformers。

This relay integrates complete transformer‑oriented protection, measurement, control and fault‑recording functions. It adopts advanced percentage differential protection with second‑harmonic inrush‑current restraint, which can reliably avoid mis‑operation during transformer energization. It also provides over‑excitation protection, thermal overload protection, phase‑overcurrent & ground‑fault protection, negative‑sequence overcurrent protection, over‑voltage/under‑voltage protection, frequency protection and RTD winding‑oil temperature over‑temperature protection for three‑winding transformers。

It can real‑time collect current, voltage, power, energy, winding‑oil temperature and harmonic data. Built‑in disturbance‑recorder captures complete fault waveforms and time‑stamped event logs, helping maintenance engineers quickly analyze fault causes and reduce power‑grid accident‑processing time. Local LCD keypad supports parameter setting, status viewing and fault diagnosis. It adopts Modbus RTU communication to realize remote monitoring and parameter configuration by upper‑level DCS system. FlexLogic flexible logic function can customize protection interlocking logic according to on‑site working‑condition requirements。

Product Details

Draw‑out panel‑mount integrated structure, convenient for on‑site replacement and maintenance. Industrial‑grade hardware design adapts to harsh power‑station and substation electromagnetic‑interference environment. This legacy transformer‑management relay has been discontinued by original manufacturer, mainly used for old‑equipment overhaul and spare‑part replacement. Please confirm CT ratio, power‑supply range and communication parameters before commissioning. Strict ESD protection shall be adopted during installation。