Overview
The basic “Current differential” element operates on current input only. Long lines with significant capacitance can benefit from charging current compensation if terminal voltage measurements are applied to the relay. The voltage input is also used for some protection and monitoring features such as directional elements, fault locator, metering, and distance backup.
For more detailed information on “Current differential” element, refer to GE, Universal Relay (UR) family of products, Version 8.0x manuals.
To see other supported elements, click here.
Setting Parameters
Modbus memory map for Setting parameters
| Products | Hex address | Register name | Range | Units | Step | Format | Default |
| L30, L90 | 3DA6 | 87L Current Differential Function | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | 3DA7 | 87L Current Differential Block | 0 to 4294967295 | — | 1 | F300 | 0 |
| " | 3DA9 | 87L Current Differential Signal Source 1 | 0 to 5 | — | 1 | F167 | 0 (SRC 1) |
| " | 3DAA | 87L Minimum Phase Current Sensitivity | 0.1 to 4 or 16 | pu | 0.01 | F001 | 20 |
| L30 | 3DAB | 87L Current Differential Tap Setting | 0.2 to 5 | — | 0.01 | F001 | 100 |
| L90 | 3DAB | 87L Current Differential Tap Setting | 0.05 to 20 | — | 0.01 | F001 | 100 |
| L30, L90 | 3DAC | 87L Current Differential Phase Percent Restraint 1 | 1 to 50 | % | 1 | F001 | 30 |
| " | 3DAD | 87L Current Differential Phase Percent Restraint 2 | 1 to 70 | % | 1 | F001 | 50 |
| " | 3DAE | 87L Current Differential Phase Dual Slope Breakpoint | 0 to 20 | pu | 0.1 | F001 | 10 |
| " | 3DAF | 87L Current Differential Ground Function | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | 3DB0 | 87L Current Differential Ground Pickup | 0.05 to 1 | pu | 0.01 | F001 | 10 |
| " | 3DB1 | 87L Current Differential Ground Restraint | 1 to 50 | % | 1 | F001 | 25 |
| " | 3DB2 | 87L Current Differential Ground Delay | 0 to 5 | seconds | 0.01 | F001 | 10 |
| " | 3DB3 | 87L Current Differential Key DTT | 0 to 1 | — | 1 | F102 | 1 (Enabled) |
| " | 3DB4 | 87L Current Differential External Key DTT | 0 to 4294967295 | — | 1 | F300 | 0 |
| " | 3DB6 | 87L Current Differential Target | 0 to 2 | — | 1 | F109 | 0 (Self-reset) |
| " | 3DB7 | 87L Current Differential Event | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| L30 | 3DB8 | 87L Current Differential Tap 2 Setting | 0.2 to 5 | — | 0.01 | F001 | 100 |
| L90 | 3DB8 | 87L Current Differential Tap 2 Setting | 0.05 to 20 | — | 0.01 | F001 | 100 |
| L90 | 3DB9 | 87L Current Differential Signal Source 2 | 0 to 6 | — | 1 | F211 | 0 (None) |
| " | 3DBA | 87L Current Differential Signal Source 3 | 0 to 6 | — | 1 | F211 | 0 (None) |
| " | 3DBB | 87L Current Differential Signal Source 4 | 0 to 6 | — | 1 | F211 | 0 (None) |
| F102 | 0 = Disabled, 1 = Enabled | ||||||
| F109 | 0 = Self-reset, 1 = Latched, 2 = Disabled | ||||||
| F167 | 0 = SRC 1, 1 = SRC 2, 2 = SRC 3, 3 = SRC 4, 4 = SRC 5, 5 = SRC 6 | ||||||
Logics & highlights
Current differential logic
