The CM-UFD.M31 grid feed-in monitoring relay monitors voltage and frequency in single-phase and three-phase networks. In conjunction with inverters with integrated island network detection, it meets the conditions for NA protection according to VDE-AR-N 4105:2018-11 (generation systems on the low-voltage network) or VDE-AR-N 4110:2018-11 (generation systems on the medium-voltage network). For use in old systems, the setting values according to VDE-AR-N 4105:2011 or BDEW (feed-in to the medium-voltage network) can also be selected. The last 99 shutdown causes and their respective times are stored in an alarm memory. The connected coupling switches are also monitored, vector shift detection and ROCOF frequency gradient monitoring is carried out.
| Property | Value |
| Voltage type for actuation: | AC/DC |
| Response value voltage: | 0 to 540 V |
| Number of contacts as changeover contact: | 3 |
| Design of the electrical connection: | Screw connection |
| Width: | 108 mm |
| Height: | 90 mm |
| Depth: | 67 mm |
| Voltage measuring range 1: | 0 to 540 V |
| Rated control supply voltage Us at AC 50 Hz: | 24 to 240 V |
| With removable terminals: | no |
| 1-phase undervoltage possible: | yes |
| 3-phase undervoltage possible: | yes |
| 1-phase overvoltage possible: | yes |
| 3-phase overvoltage possible: | yes |
| 1-phase window possible: | yes |
| 3-phase window possible: | yes |
| Includes DC undervoltage function: | no |
| Includes DC overvoltage function: | no |
| Contains DC voltage window function: | no |
| Type of voltage of the measuring range: | AC |
| Rated control supply voltage Us at AC 60 Hz: | 24 to 240 V |
| Rated control supply voltage Us at DC: | 24 to 240 V |
