Reducing transformer inrush current

A controller comprising:

• processing circuitry;
• and
• data storage storing instructions executable by said processing circuitry whereby said controller is operative to perform the method of:
• between a switching device and a voltage source, monitoring a voltage in one of the phases;
• for each of a sequence of iterations:
• at a same opening angle relative to a reference angle of the monitored voltage, starting an opening sequence of the switching device, opening the switching device;
• at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device, closing the switching device;
• obtaining an indication of a peak value of an overall inrush current resulting from the closing of the switching device;
• and
• selecting for future use with said same opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence.

A switching device comprising:

• a controller;
• processing circuitry;
• and
• data storage storing instructions executable by said processing circuitry whereby said controller is operative to perform the method of:
• between a switching device and a voltage source, monitoring a voltage in one of the phases;
• for each of a sequence of iterations:
• at a same opening angle relative to a reference angle of the monitored voltage, starting an opening sequence of the switching device, opening the switching device;
• at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device, closing the switching device;
• obtaining an indication of a peak value of an overall inrush current resulting from the closing of the switching device;
• selecting for future use with said same opening angle the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence,
• a voltage sensor for the monitoring of the voltage, and
• an inrush sensor for the obtaining of the indication of a peak value of the overall inrush current.

An electrical system comprising:

• a controller;
• processing circuitry;
• and
• data storage storing instructions executable by said processing circuitry whereby said controller is operative to perform the method of:
• between a switching device and a voltage source, monitoring a voltage in one of the phases;
• for each of a sequence of iterations:
• at a same opening angle relative to a reference angle of the monitored voltage, starting an opening sequence of the switching device opening the switching device;
• at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device, closing the switching device;
• obtaining an indication of a peak value of an overall inrush current resulting from the closing of the switching device;
• and
• selecting for future use with said same opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence,
• a voltage sensor for the monitoring of the voltage,
• an inrush sensor for the obtaining of the indication of a peak value of the overall inrush current,
• the switching device, and
• the transformer.

A computer program product comprising computer-executable components for causing a controller to perform the method of:

• between a switching device and a voltage source monitoring a voltage in one of the phases;
• for each of a sequence of iterations:
• at a same opening angle relative to a reference angle of the monitored voltage, starting an opening sequence of the switching device, opening the switching device;
• at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, starting a closing sequence of the switching device, closing the switching device;
• obtaining an indication of a peak value of an overall inrush current resulting from the closing of the switching device;
• selecting for future use with said same opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence;
• and
• when the computer-executable components are run on processing circuitry comprised in the controller.