| Model Features | SEL-787-2X | SEL-787-21 | SEL-787-2E | SEL-787-3E | SEL-787-3S | SEL-787-4X | |
|---|---|---|---|---|---|---|---|
| Windings Protected | 2 | 2 | 2 | 3 | 3 | 4 | |
| CT/PT Inputs | |||||||
| Phase Voltage Inputs | 0 | 0 | 3 | 3 | 3 | 0 | |
| Differential Current Inputs | 6 | 6 | 6 | 9 | 9 | 12 | |
| Neutral Current | 0 | 1 | 1 | 1 | 0 | 0 | |
| VS/VBAT Channel | 0 | 0 | 0 | 0 | 1 | 0 | |
| Differential and Restricted Earth Fault (REF) Elements | |||||||
| Differential Protection Windings (Standard) | 2 | 2 | 2 | 3 | 3 | 4 | |
| REF Elements (Standard) | 0 | 1 | 1 | 1 | 0 | 0 | |
| Differential Protection Windings (Winding 3 Configured for REF) | 2 | 2 | 3 | ||||
| REF Elements (Winding 3 Configured for REF) | 2 | 2 | 2 | ||||
| Protection Elements | |||||||
| 24 | Volts/Hertz | ||||||
| 25 | Synchronism Check | ||||||
| 27I | Inverse-Time Undervoltage (Phase, Phase-to-Phase, Sequential, Vsync) | ||||||
| 27P | Undervoltage (Phase) With Inverse Characteristic | ||||||
| 27PP | Phase-to-Phase Undervoltage | ||||||
| 27S | VS Channel Undervoltage | ||||||
| 32 | Directional Power | ||||||
| 49RTD | Resistance Temperature Detectors (RTDs) | ||||||
| 50N | Neutral Overcurrent | ||||||
| 50 (P,G,Q) | Overcurrent (Phase, Ground, Neg. Seq.) | ||||||
| 51 (P,G,Q) | Time Overcurrent (Phase, Ground, Neg. Seq.) | ||||||
| 51N | Neutral Time Overcurrent | ||||||
| 51PC | Combined Winding Phase Time Overcurrent | ||||||
| 51GC | Combined Winding Ground Time Overcurrent | ||||||
| 59 (P,G,Q) | Overvoltage (Phase, Ground, Neg. Seq.) | ||||||
| 59 | Overvoltage (Synchronism or Battery Voltage) | ||||||
| 59I | Inverse-Time Overvoltage (Phase, Phase-to-Phase, Sequential, Vsync) | ||||||
| 59S | VS Channel Overvoltage | ||||||
| 59Q | Negative-Sequence Overvoltage | ||||||
| 81 (O,U) | Over-/Underfrequency | ||||||
| 87 | Phase Differential | ||||||
| Model Features | SEL-787-2X | SEL-787-21 | SEL-787-2E | SEL-787-3E | SEL-787-3S | SEL-787-4X | |
|---|---|---|---|---|---|---|---|
| Additional Functions | |||||||
| 85RIO | SEL Mirrored Bits Communications | ||||||
| BF | Breaker Failure | ||||||
| BW | Breaker Wear Monitoring | ||||||
| DFR | Event Reports | ||||||
| ENV | SEL-2600 RTD Module Support* | ||||||
| LDP | Load Data Profiling | ||||||
| LGC | SELogic Control Equations | ||||||
| LOP | Loss of Potential | ||||||
| MET | High-Accuracy Metering | ||||||
| RTD | 10 Internal or 12 External (See ENV) RTD Inputs* | ||||||
| REF | Restricted Earth Fault | ||||||
| RTU | Remote Terminal Unit | ||||||
| SER | Sequential Events Recorder | ||||||
| TFE | Through-Fault Event Monitor | ||||||
| PMU | Synchronized Phasor Measurement | ||||||
*Optional feature