Circuit breaker device and method

A circuit breaker device for protecting an electrical low-voltage circuit, the circuit breaker device comprising:

• a housing of the circuit breaker having connections to be connected to conductors of the low-voltage circuit;
• a voltage sensor for ascertaining a voltage level of the low-voltage circuit and making instantaneous voltage values available, the instantaneous voltage values being phase angle-related threshold values made available for each phase angle or a phase angle range having multiple phase angles or a phase angle section being part of a phase angle;
• an electronic interruption unit including semiconductor-based switching elements having a high-resistance state of said switching elements for interrupting, and a low-resistance state of said switching elements for allowing, current to flow in the low-voltage circuit;
• and
• a control unit connected to said voltage sensor and to said electronic interruption unit;
• the circuit breaker device configured to:
• make instantaneous threshold values available,
• compare the instantaneous voltage values with the instantaneous threshold values in terms of phase angle by comparing a threshold value for a phase angle with a voltage value for the same phase angle of the voltage,
• upon the instantaneous threshold values being exceeded or undershot, or a differential voltage value being formed from the instantaneous threshold value and the instantaneous voltage value, compare the differential voltage value with a differential voltage threshold value, and
• upon the threshold value being exceeded or undershot, initiate an interruption of the low-voltage circuit by said electronic interruption unit including said semiconductor-based switching elements to avoid a short-circuit current.