Voltage and frequency relay, NA protection according to VDE AR-N 4105. Network and system protection in accordance with the VDE application rules VDE-AR-N 4105:2011-06 and 4105:2018-11, VDE-AR-N 4110:2018-11. Compliance with the BDEW guideline and DIN V VDE 0126-1-1, DIN V VDE V 0126-1-1/A1. Monitoring of overvoltage and undervoltage and frequency, 10-minute average vector shift monitoring ROCOF, monitoring of the frequency gradient df/dt. Single-fault safe with monitoring of the coupling switch, island network monitoring (passive). Integrated 4-digit digital display for measured values and programming. All values can be set and read on the device. Preset basic programs in accordance with the standards and guidelines, digital display for measured values and programming of limit values. Hysteresis and switching times can be set individually for each alarm. MIN/MAX memory for measured values, test button and simulation function with measurement of switching times. Integrated alarm counter for 100 alarms, with relative time stamp and recording of the total alarm time. Switching outputs: Output relay 2 x 1 changeover contact, transistor outputs for reporting the switching cause. Operating status and alarm display with LEDs. Possibility of code protection for parameters and sealing for setting values.