Application Research Of The New Intelligent Reactive Power Compensation In Low Voltage

In recent years, the inductive load is being used more and more common in urban and rural low-voltage power grid, so with the low-voltage reactive power compensation technology. But the current reactive compensation device is using with large size, difficult to maintain and reliable issues is weaknesses. And it’s important to develop a new type of intelligent low-voltage reactive power compensation device.By a summary of reactive power compensation principle and the shortcomings of traditional reactive compensation device in the practical application in this paper, a new type of intelligent reactive power compensation device is designed for 380 V low-voltage gird. The device can accurately collecting and calculating gird parameter values, with which to calculated the required capacity in using of capacitors, and switch the capacitor in zero-voltage and zero-current time by using the magnetic latching relays to compensate reactive power in low-voltage grid and improve the power gird quality.In this paper, the intelligent low-voltage reactive power compensation device consists of one or more integrated intelligent compensation capacitor modules, one of every intelligent module could be set as master to switch itself and other intelligent modules.The hardware circuit including voltage and current sampling, voltage and current zero-crossing detection, driving the magnetic latching relay, RS485 communication,human interface and key-press detection are designed. While the software for the intelligent capacitor module is designed to sample and calculate the gird voltage and current with FFT algorithm for system parameter of analysis and calculation, detect the zero-crossing points. At the same time, the implementation of the softwareprogramming is helped with the Cube Mx and Matlab.To verified the signal acquisition and processing in intelligent module, a experiment is designed to compare with the special measuring chip and it shows a more accuracy result. The paper also designed a relay zero-switching simulation experiment, to achieve a capacitor-in when voltage zero-crossing, and the capacitor-out when current zero-crossing which reduced the inrush current caused by switching capacitor.By building a simulation gird, and test the new type of low-voltage reactive power compensation device, the intelligence device can quickly detect gird parameters and control the capacitor to switch effectively and maintain the power factor within the set target range. The compensation shows a good effect result, and the power quality is improved as the desired effect.