Overview
The steady-state frequency of a power system is a certain indicator of the existing balance between the generated power and the load. Whenever this balance is disrupted through the loss of an important generating unit or the isolation of part of the system from the rest of the system, the effect is a reduction in frequency. For more detailed information on “Underfrequency” 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 |
| B30, D30, D60, F35, F60, G30, G60, L30, L90, M60, N60, T35, T60 | CC23 | Underfrequency 1 Function | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | CC24 | Underfrequency 1 Block | 0 to 4294967295 | — | 1 | F300 | 0 |
| " | CC26 | Underfrequency 1 Min Current | 0.1 to 1.25 | pu | 0.01 | F001 | 10 |
| " | CC27 | Underfrequency 1 Pickup | 20 to 65 | Hz | 0.01 | F001 | 5950 |
| " | CC28 | Underfrequency 1 Pickup Delay | 0 to 65.535 | s | 0.001 | F001 | 2000 |
| " | CC29 | Underfrequency 1 Reset Delay | 0 to 65.535 | s | 0.001 | F001 | 2000 |
| " | CC2A | Underfrequency 1 Source | 0 to 5 | — | 1 | F167 | 0 (SRC 1) |
| " | CC2B | Underfrequency 1 Events | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | CC2C | Underfrequency 1 Target | 0 to 2 | — | 1 | F109 | 0 (Self-reset) |
| " | CC2D | Reserved (5 items) | 0 to 1 | — | 1 | F001 | 0 |
| " | CC32 | …Repeated for Underfrequency 2 | |||||
| " | CC41 | …Repeated for Underfrequency 3 | |||||
| " | CC50 | …Repeated for Underfrequency 4 | |||||
| " | CC5F | …Repeated for Underfrequency 5 | |||||
| " | CC6E | …Repeated for Underfrequency 6 | |||||
| B30 | CC7D | …Repeated for Underfrequency 7 | |||||
| " | CC8C | …Repeated for Underfrequency 8 | |||||
| " | CC9B | …Repeated for Underfrequency 9 | |||||
| " | CCAA | …Repeated for Underfrequency 10 | |||||
| " | CCB9 | …Repeated for Underfrequency 11 | |||||
| " | CCC8 | …Repeated for Underfrequency 12 |
| 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
Underfrequency logic
