Fault managed power method for ac powering systems

An apparatus comprising:

• an alternating current (AC) power source to provide AC power comprising an AC voltage waveform and an AC current waveform;
• a pair of lines configured to carry the AC power from the AC power source;
• a switch circuit connected to the pair of lines and configured to either connect the AC power to the pair of lines or disconnect the AC power from the pair of lines;
• an analog-to-digital converter coupled to receive the AC voltage waveform and the AC current waveform carried on the pair of lines and to convert the AC voltage waveform and the AC current waveform to digital data;
• and
• a processor coupled to the analog-to-digital converter and to the switch circuit, wherein the processor is configured to:
• derive at least one characteristic of an AC voltage waveform and an AC current waveform on the pair of lines;
• select one of a plurality of predetermined waveform characteristics as a selected waveform characteristic to be used as a trigger for fault detection;
• control the switch circuit to disconnect the AC power from the pair of lines upon occurrence of the selected waveform characteristic;
• perform a fault detection during a safety check time window while the AC power is disconnected;
• and
• control the switch circuit to reconnect the AC power to the pair of lines when no fault is detected during the safety check time window.

A method comprising:

• determining a phase position of an alternating current (AC) voltage waveform at which a non-zero line voltage exists while current flow is below a threshold;
• disconnecting AC power from a pair of lines at the phase position;
• performing fault detection during a safety check time window using voltage present on the pair of lines resulting from the AC voltage waveform;
• and
• reconnecting AC power when no fault is detected.