Investigation of selected properties of type F residual current circuit breakers

In low-voltage electrical installations, power electronic converters are more widely used (in photovoltaic systems, charging systems for electric vehicles, variable-speed drive systems), and they affect the selection of the type of tripping of residual current devices (AC, A, F or B). In circuits where a residual current having components of a frequency other than 50 Hz appears, it may be necessary to use a type F residual current device. The article discusses the testing of the tripping threshold of this type of residual current devices at residual currents with frequencies other than 50 Hz. The response of type F residual current devices to the measurement of the earth fault loop impedance performed with two meters differing in the measuring current flow time is presented as well. The obtained results indicate which meter should be selected so that there is no (Testing of selected properties of type F residual current devices).