Intelligent circuit breaker providing synchronous switching and condition monitoring

A method for operating a synchronous control unit (SCU) for synchronously switching a switching device coupled to a switched circuit carrying a current or voltage waveform, said SCU having a target switching time (T.sub.BASE) and wherein a switching time substantially corresponding with a target point on the waveform is determined, comprising the steps of:

• (a) determining an electrical and mechanical system adaptation adjustment factor (.DELTA.T.sub.Adapt);
• (b) receiving sensor inputs for temperature, control voltage, operating mechanism energy, and operating signal history, and then determining a compensation adjustment factor (.DELTA.T.sub.Comp);
• (c) receiving sensor inputs for system voltage and system current, and then determining a system current and/or voltage target for synchronous switching;
• (d) determining an estimated operating time of the switching device (T.sub.Est);
• (e) calculating an operating time delay to actuate the switching device at the target system voltage and current if an operating signal, indicating that the switching device is to be opened or closed, were received now by the SCU;
• and
• (f) determining whether an operating signal has been received and, if so:
• causing the switching device to operate so as to synchronously switch in accordance with the calculated operating time delay and the voltage or current target and, if not:
• not causing the switching device to operate.