Method for monitoring vacuum interrupter's condition and an electric switching device

An electronic device comprising:

• one or more processors;
• and
• a computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by the one or more processors of the electronic device, cause the electronic device to
• receive a first voltage signal indicating a first voltage between a source line and a first contact of a switch inside an electric device, the first contact of the switch coupled to the source line,
• receive a second voltage signal indicating a second voltage between a second contact of the switch and a reactive component, the second contact of the switch coupled to the reactive component,
• receive a current signal indicating a current at the second contact of the switch,
• determine an occurrence of a restrike in response to determining a simultaneous increase in amplitudes of the first voltage signal, the second voltage signal, and the current signal, and
• determine a condition of a vacuum interrupter based on the determined occurrence of the restrike, wherein determining the condition of the vacuum interrupter based on the determined occurrence of the restrike comprises either
• counting a number of switching operations, between open and closed, performed by the switch in a time period, counting a number of determined occurrences of the restrike in the time period, computing a ratio of the counted number of the determined occurrences of the restrike to the counted number of the switching operation, and determining an unacceptable vacuum condition in response to determining that the computed ratio exceeds a predetermined ratio value, or
• in response to determining the restrike, counting a number of switching operations, between open and closed, that are performed by the switch in a time period between the restrike and a subsequent determined restrike, and determining an unacceptable vacuum interrupter's condition in response to the number of the switching operations being below a predetermined number.

A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by the one or more processors of an electronic device, cause the electronic device to:

• receive a first voltage signal indicating a first voltage between a source line and a first contact of a switch inside an electric device, the first contact of the switch coupled to the source line;
• receive a second voltage signal indicating a second voltage between a second contact of the switch and a reactive component, the second contact of the switch coupled to the reactive component;
• receive a current signal indicating a current at the second contact of the switch;
• determine an occurrence of a restrike in response to determining a simultaneous increase in amplitudes of the first voltage signal, the second voltage signal, and the current signal;
• and
• determine a condition of a vacuum interrupter based on the determined occurrence of the restrike, wherein determining the condition of the vacuum interrupter based on the determined occurrence of the restrike comprises either
• counting a number of switching operations, between open and closed, performed by the switch in a time period, counting a number of determined occurrences of the restrike in the time period, computing a ratio of the counted number of the determined occurrences of the restrike to the counted number of the switching operation, and determining an unacceptable vacuum condition in response to determining that the computed ratio exceeds a predetermined ratio value, or
• in response to determining the restrike, counting a number of switching operations, between open and closed, that are performed by the switch in a time period between the restrike and a subsequent determined restrike, and determining an unacceptable vacuum interrupter's condition in response to the number of the switching operations being below a predetermined number.