AC/DC sensitive residual current monitoring

Having fault currents under control at all times –
Inverters used in earthed systems

DIN V VDE V 0126-1-1 (VDE 0126-1-1):2006-02 specifies that inverters without galvanic isolation used in photovoltaic systems are to be equipped with a residual current monitoring device (RCMA).

The RCMA126 (278) residual current monitoring module fulfills the requirements with respect to the switching device integrated in the inverter, hence ensuring a safe and standard-compliant operation.

Residual current monitoring is carried out using an internal measuring current transformer. The r.m.s. value is calculated by summing up the DC components included in the residual current and the AC components that are below the cut-off frequency. A signal in proportion to the residual current is provided at the module output (X1). Then this output signal can be used to activate the switching device.

Technical features

• AC/DC sensitive residual current measurement 0…100 mA
• Frequency range 0…500 Hz
• Monitoring of the connection to the measuring current
  transformer
• Various output options