Abstract: An adaptive sequential controller (480) for controlling a single-phase circuit breaker, multiple circuit breakers in a multi-phase configuration, or a multi-phase circuit breaker to substantially eliminate transients upon closing the circuit breaker and to minimize switching energy when the circuit breaker for any phase of the line is open. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental affects. To control the circuit breaker so that is closes at a zero crossing of the voltage waveform, the adaptive sequential controller includes a potential transformer (70) that is connected to the distribution line. The potential transformer provides a reference signal corresponding to the zero crossing or zero instance of the voltage waveform. If the power factor of the load coupled to the line is known and remains relatively constant, a current transformer is not required.

Abstract: An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened.