VMD423-D-2, voltage relay

Voltage relays

LINETRAXX ® VMD423 / VMD423HProduct description The feed-in to the public low-voltage network is a voltage and frequency monitoring for the decoupling of self-production systems > 30 kW (e.g. cogeneration, wind, hydropower and photovoltaic systems) according to DIN V VDE V 0126-1-1. The three-phase voltage and frequency monitoring relays of the VMD423 series continuously monitor the voltage and frequency in the public network at the feed-in. When fed into the medium voltage network, the output voltages and frequencies of the voltage converters (100 V) are measured. They switch when over- or If an alarm relay is below limit values within ≤ 80 ms (response values in accordance with the BDEW Directive "Self-generating systems on the medium voltage network"). An overvoltage (> U2), measured as a mean over a 10-minute period, leads to the switching of an alarm relay. The voltages are measured as effective values. In addition, asymmetry, phase failure and phase sequence are monitored. The VMD423 is multifunctional and can be adapted to all requirements of the EVA. The current values are permanently displayed on the LC display. The measured value leading to the switching of the alarm relay is stored. The system operators' requirements can be taken into account by means of adjustable start-up and return times: B. device-related start-up phases, short-term voltage changes, etc. The VMD423 series requires a separate supply voltage, while the VMD423H variant is supplied from the network itself. During this time, changes in the measured voltage and frequency have no effect on the switching state of the alarm relays and display of the alarm LEDs. The devices have several separately adjustable measuring channels (over / under voltage, over / under frequency). If the measurement size exceeds or below the response value, the set response delays start "ton1 / 2." After the response delay is over, the alarm relays and the alarm LEDs turn on. The set drop delay "toff" starts below or above the measurement size after switching the alarm relay. After the end of "toff" the alarm relay will turn back into the initial position. If the error storage is activated, the alarm relays remain in alarm position until the reset key is activated. After voltage reversing, the alarm message remains active for the time of the adjustable start delay "t.".