Application Scenarios
A large petrochemical complex in the Gulf Coast region experienced recurring feeder trips on its main distribution switchgear during summer peak-load periods. The trips originated from transient overloads on motor control center feeders that the existing electromechanical relays could not discriminate from true faults. The plant’s electrical team replaced the legacy relays with GE 750-P5-G5-S5-HI-A20-R-E units configured for the plant’s 5 A CT secondary circuits.
The new relays provided time-overcurrent protection with multiple setpoint groups, allowing different protection curves for normal and emergency operating conditions. After commissioning, the plant recorded zero nuisance trips during the following summer peak season. The GE 750-P5-G5-S5-HI-A20-R-E‘s built-in waveform capture capability also enabled the electrical team to analyze a genuine cable fault event and confirm the protection operated correctly. According to the plant’s electrical supervisor, the relay’s draw-out chassis design simplified periodic testing, reducing maintenance time per feeder by approximately 40% compared to the previous fixed-mount relays.
Parameter
| Parameter | Value/Description |
|---|---|
| Product Model | GE 750-P5-G5-S5-HI-A20-R-E |
| Manufacturer | GE Multilin (General Electric) |
| Product Category | Feeder Management Relay (Numerical Protection Relay) |
| Series | SR750 Series |
| Phase CT Inputs (P5) | 5 A nominal |
| Ground CT Input (G5) | 5 A nominal |
| Digital Inputs (S5) | 5 channels |
| Output Relays (S5) | 5 relays |
| Control Power (HI) | High-range control power supply |
| Analog Input Channels (A20) | 20 channels |
| Communication (R) | RS-232 and RS-485 ports |
| Enclosure (E) | Draw-out chassis with dust-proof door |
| Protection Functions | Time overcurrent, frequency, overvoltage, ground fault |
| Setpoint Groups | 4 |
| Operating Temperature | −40 °C to +60 °C (−40 °F to +140 °F) |
| Dimensions | Approx. 7″ W × 6.5″ L × 8.5″ H |
| Weight | Approx. 7.9 kg |
| Lifecycle Status | Discontinued by manufacturer |
