Method of performing circuit opening and closing operation, computer program, control system and power system

A non-transitory computer-readable storage medium comprising instructions which, when executed by processing circuitry of a control system, causes the control system to perform, or command performance of, a method of performing a circuit opening and closing operation in a power system having a first phase, a second phase lagging the first phase by 120°, a third phase lagging the first phase by 240°, a three-phase transformer including Y-connected primary windings with ungrounded neutral or delta connected primary windings, and a circuit breaker system connected to the transformer, the method including:

• a) controlling the circuit breaker system to open the first phase, the second phase and the third phase simultaneously or essentially simultaneously such that a reference current of a reference phase among the first phase, the second phase and the third phase is interrupted first at a first current zero crossing of the reference current after the opening;
• and
• b) controlling the circuit breaker system to close the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase among the first phase, the second phase and the third phase which is lagging the reference phase by 120°, in a time range from 90° before a negative peak of said phase to ground voltage to 90° after the negative peak of said phase to ground voltage if the current zero crossing is a positive current zero crossing, or in a time range from 90° before a positive peak of said phase to ground voltage to 90° after the positive peak of said phase to ground voltage if the current zero crossing is a negative current zero crossing.

A control system for controlling a circuit breaker system connected to a three-phase transformer and to a three-phase power source having a first phase, a second phase lagging the first phase by 120°, and a third phase lagging the first phase by 240°, the transformer including Y-connected primary windings with ungrounded neutral or delta connected primary windings, wherein the control system comprises:

• processing circuitry, and
• a non-transitory computer-readable storage medium including instructions which, when executed by the processing circuitry, causes the control system to perform, or command performance of, a method including the steps of
• a) controlling the circuit breaker system to open the first phase, the second phase and the third phase simultaneously or essentially simultaneously such that a reference current of a reference phase among the first phase, the second phase and the third phase is interrupted first at a first current zero crossing of the reference current after the opening;
• and
• b) controlling the circuit breaker system to close the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase among the first phase, the second phase and the third phase which is lagging the reference phase by 120°, in a time range from 90° before a negative peak of said phase to ground voltage to 90° after the negative peak of said phase to ground voltage if the current zero crossing is a positive current zero crossing, or in a time range from 90° before a positive peak of said phase to ground voltage to 90° after the positive peak of said phase to ground voltage if the current zero crossing is a negative current zero crossing.

A power system comprising:

• a three-phase transformer including Y-connected primary windings with ungrounded neutral or delta connected primary windings;
• a circuit breaker system connected to the transformer, the circuit breaker system having a first pole, a second pole and a third pole that are configured to connect to a three-phase power source having a first phase, a second phase lagging the first phase by 120°, and a third phase lagging the first phase by 240°;
• an actuating device configured to actuate the first pole, the second pole and the third pole;
• and
• a control system configured to:
• a) control the actuating device to open the first phase, the second phase and the third phase simultaneously or essentially simultaneously such that a reference current of a reference phase among the first phase, the second phase and the third phase is interrupted first at a first current zero crossing of the reference current after the opening;
• and
• b) control the actuating device to close the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase among the first phase, the second phase and the third phase which is lagging the reference phase by 120°, in a time range from 90° before a negative peak of said phase to ground voltage to 90° after the negative peak of said phase to ground voltage if the current zero crossing is a positive current zero crossing, or in a time range from 90° before a positive peak of said phase to ground voltage to 90° after the positive peak of said phase to ground voltage if the current zero crossing is a negative current zero crossing.