Method and apparatus for controlling a circuit breaker in an electrical energy supply network

A system with an apparatus for controlling a circuit breaker in an electrical energy supply network and a control unit, the apparatus comprising:

• a signal input for receiving a switching signal generated by a protective or control device of the energy supply network;
• a signal output for outputting a switching signal to a control unit of the circuit breaker;
• the apparatus being configured to check a current flowing through the circuit breaker for the occurrence of zero crossings;
• the apparatus being configured to prevent forwarding of the switching signal to the control unit until at least one zero crossing has been detected;
• the apparatus being configured to use a current transformer to record the current flowing through the circuit breaker, wherein the current transformer has a primary side and a secondary side;
• and
• the apparatus being configured to subject a current profile output by the current transformer on the secondary side to a correction in order to model a DC element, contained in a current present on the primary side, on the secondary side;
• wherein the control unit includes a switch drive of the circuit breaker, wherein the control unit is configured, by means of the switch control device, to determine after receipt of the switching signal an optimal switching time of the circuit breaker and to control the switch drive accordingly to open the circuit breaker as close as possible to a current zero crossing.

A method for controlling a circuit breaker in an electrical energy supply network, the method comprising:

• generating a switching signal by way of a protective or control device of the energy supply network;
• monitoring a current flowing through the circuit breaker and checking the current for an occurrence of zero crossings;
• transmitting the switching signal to a control unit of the circuit breaker only after at least one zero crossing has been detected, the switching signal causing the control unit to open switching contacts of the circuit breaker;
• using a current transformer to record the current flowing through the circuit breaker;
• and
• subjecting a current profile output by the current transformer on a secondary side to a correction in order to model a DC element, contained in a current present on the primary side, on the secondary side.

An apparatus for controlling a circuit breaker in an electrical energy supply network, the apparatus comprising:

• a signal input for receiving a switching signal generated by a protective or control device of the energy supply network;
• a signal output for outputting a switching signal to a control unit of the circuit breaker;
• the apparatus being configured to check a current flowing through the circuit breaker for the occurrence of zero crossings;
• the apparatus being configured to prevent forwarding of the switching signal to the control unit until at least one zero crossing has been detected;
• the apparatus being configured to use a current transformer to record the current flowing through the circuit breaker;
• and
• the apparatus being configured to subject a current profile output by the current transformer on a secondary side to a correction in order to model a DC element, contained in a current present on the primary side, on the secondary side.