Design of an intelligent low-voltage power capacitor

As to the disadvantages of large size, complex internal structure, bad maintainability, inflexible application of the traditional reactive power compensation devices, a new intelligent low-voltage power capacitor based on LPC2388 processor is proposed, which takes the power factor and reactive power as the controlling quantity while considering the effect of voltage. The device can achieve the functions of zero-cross switching of capacitor, including turning on the switch while the voltage is zero and turning off the switch while the current is zero. With the control strategy of seven-zone diagram, it can effectively prevent the concussion of switching and realize fast and accurate switching of capacitor. Different devices can communicate with each other by RS485. Users can choose the type and quantity of this device to form low voltage reactive compensation equipment satisfying with various load requirements. The experiment results show that, the device proposed in this paper can reduce reactive power effectively and can play an important role in reducing reactive loss in the power line and improving the security of power grid.