Digital guide
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GE SR750-P5-G5-S5-LO-A1-R
Product Name: GE Multilin SR750 Feeder Management & Protection Relay
Product Introduction: The SR750 is a microprocessor-based feeder protection and management relay fromGE Grid Solutions (Multilin series). The order code decodes as: P5 = 5 A nominal CT secondary current inputs; G5 = 5 A zero-sequence (ground) current input; S5 = 5 A sensitive ground current input; LO = Low control power range (20–60 VDC or 20–48 VAC); A1 = standard configuration; R = revision.
Detailed content
Technical Specifications:
- Current Inputs: P5 = 5 A phase CT; G5 = 5 A ground CT; S5 = 5 A sensitive ground CT
- Auxiliary Power (LO): 20–60 VDC / 20–48 VAC
- Protection Functions: 50/51, 50N/51N, 27/39, 81U/81O, 46, 47, voltage-restrained overcurrent
- Communication: RS-232/RS-485, optional Modbus RTU / DNP3.0
- Display: Front-panel LCD with keypad
- Digital Inputs: 8 programmable optically isolated
- Output Relays: Up to 6 Form-C programmable contacts
- Operating Temperature: –40 °C to +85 °C
Functional Features: Dual-processor architecture (Motorola 68332 measurement processor + communication/display processor); 128 samples/cycle; 64-cycle waveform capture; comprehensive self-diagnostics; event recording.
Application Scenarios: Medium-voltage switchgear in utility substations (13.8 kV–69 kV distribution feeders), industrial plant distribution systems, bus protection schemes, transformer backup protection, and legacy retrofit replacements for electromechanical relays (GE MIF/MIF II, Multilin 239, 735/737).
Installation & Usage Notes: Verify the “LO” power code matches available station service — LO relays require 20–60 VDC / 20–48 VAC; never feed 24 VDC to an HI-coded relay or vice versa. Configure G5 (zero-sequence) and S5 (sensitive ground) separately for proper ground fault protection.
