GE Multilin SR750-P1-G1-S1-HI-A20-G Feeder Management & Protection Digital Relay

Manufacturer: GE Vernova (GE Multilin Digital Energy)

Part Number: SR750-P1-G1-S1-HI-A20-G (750 series feeder protection relay, drawout chassis)

Model Code Decoding: SR750 = Base platform (medium voltage feeder protection relay) P1 = 1×1A phase CT current input G1 = 1×1A zero-sequence ground CT input S1 = 5A sensitive ground fault input HI = Wide-range universal control power 70–265VAC / 88–300VDC A20 = 8 isolated 4–20mA analog output channels -G = No RTD temperature monitoring board (without thermal measurement function)

Product Type: Drawout multi-function digital feeder protection, metering, control & fault recording relay

Matching Platform: Medium/low voltage power distribution switchgear, industrial plant MCC, utility substation feeder cabinet, SCADA DCS remote monitoring system

Core Function: Full set of feeder protection logic; high-precision electrical metering; breaker automatic control & synchrocheck; waveform capture + SOE event sequence recording; multi-standard communication interface; 8-channel isolated 4–20mA analog output; programmable logic control (PLC-like logic); breaker wear monitoring & maintenance alarm; IRIG-B time synchronization; conformal coated PCB for harsh industrial environments

1. Product Overview

SR750-P1-G1-S1-HI-A20-G is the classic flagship digital feeder protection relay of GE Multilin SR750 series, widely used for primary protection and full-cycle management of medium-voltage distribution feeders, also serving as backup protection for transformers, busbars and factory power lines. Adopts pluggable drawout drawer structure, allowing hot replacement without powering off the whole switchgear cabinet to reduce power outage maintenance time. Equipped with complete multi-level protection algorithms covering phase short circuit, overload, directional ground fault, sensitive residual ground fault, negative sequence overcurrent, over/under voltage, underfrequency, reverse power, breaker failure protection, etc., effectively isolating feeder faults to prevent power grid cascading trips. Built-in high-precision multi-function metering module, real-time measuring voltage, current, active/reactive power, power factor, frequency, electric energy, demand value and phasor diagrams, supporting energy statistics and load monitoring. 8 independent galvanically isolated 4–20mA analog outputs can convert any measured electrical quantity into standard analog signals for DCS/PLC closed-loop regulation. Supports waveform fault recording, millisecond-level SOE event sequence recording, breaker operation counter and wear degree calculation, automatically alarming when maintenance thresholds are reached. Standard front-panel RS232, rear dual RS485 communication ports, compatible with Modbus RTU, DNP3.0 protocols for seamless access to substation SCADA and plant control systems. Wide-range HI power supply design adapts to 220VAC, 110VDC, 250VDC common station control power without customized power modules. This variant (-G) omits RTD temperature measurement, focusing purely on electrical protection, metering and control functions. Conformal coated circuit board resists humidity, dust and corrosive gas, suitable for chemical plants, thermal power plants, offshore platforms and other harsh industrial sites. Cannot operate standalone; must be matched with CT/PT secondary wiring and switchgear auxiliary contact signal loops to realize full feeder protection and control logic. This relay is a mainstream spare replacement device for power plant and industrial distribution switchgear cabinets, used for cabinet transformation, feeder protection loop fault replacement and regular power system overhaul.

2. Complete Technical Specifications

3. Core Hardware Advantages

4. Typical Application Scenarios