A control device to synchronously sample AC voltage and current and to accurately compute the parameters

including voltage

current

active power

reactive power and power factor

is presented

which is based on the technologies of DSP

CPLD and high-speed A/D converter.By measuring the DC voltage of capacitors

environmental temperature

and historical switch-on and switch-off data of circuit-breakers

the acting time of the circuit-breakers can be predicted with this device

and the synchronous switch of capacitor bank can be realized.Moreover

reactive power can be compensated

and the harm of inrush current and overvoltage can be reduced by using the device with integrated control policy.A number of tests indicate that the dispersion of the device is smaller under similar environment of temperature and voltage

and the circuit-breaker can realize synchronous control through temperature and voltage compensation.