Overview
The “Thermal overload protection” element corresponds to the IEC 255-8 standard and is used to detect thermal overload conditions in protected power system elements. Choosing an appropriate time constant element can be used to protect different elements of the power system.
For more detailed information on “Thermal overload protection” 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 |
| All except B90, C30, M60 | 4E4B | Thermal Protection 1 Function | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | 4E4C | Thermal Protection 1 Source | 0 to 5 | — | 1 | F167 | 0 (SRC 1) |
| " | 4E4D | Thermal Protection 1 Base Current | 0.2 to 3 | pu | 0.01 | F001 | 80 |
| " | 4E4E | Thermal Protection 1 K Factor | 1 to 1.2 | — | 0.05 | F001 | 110 |
| " | 4E4F | Thermal Protection 1 Trip Time Constant | 0 to 1000 | min. | 1 | F001 | 45 |
| " | 4E50 | Thermal Protection 1 Reset Time Constant | 0 to 1000 | min. | 1 | F001 | 45 |
| " | 4E51 | Thermal Protection 1 Minimum Reset Time | 0 to 1000 | min. | 1 | F001 | 20 |
| " | 4E52 | Thermal Protection 1 Reset | 0 to 4294967295 | — | 1 | F300 | 0 |
| " | 4E54 | Thermal Protection 1 Block | 0 to 4294967295 | — | 1 | F300 | 0 |
| " | 4E56 | Thermal Protection 1 Target | 0 to 2 | — | 1 | F109 | 0 (Self-reset) |
| " | 4E57 | Thermal Protection 1 Events | 0 to 1 | — | 1 | F102 | 0 (Disabled) |
| " | 4E58 | Reserved (2 items) | — | — | — | F001 | 0 |
| " | 4E5A | Repeated for Thermal Protection 2 |
| 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
Definitions
IEC 255-8 sample operate and reset curves
Definitions
Typical time constants
Thermal overload protection logic
