Research And Implementation Of Intelligent Integrated Low Voltage Reactive Power Compensation System

With the growth of my country’s economy,power consumption in society has shown an upward trend year by year,and the increase in power consumption has higher and higher requirements for the power quality of my country’s power system.Therefore,it is necessary to reduce power loss from all aspects of power transmission and distribution in the power grid.,And reactive power compensation is an important measure to achieve this goal.This paper designs and implements a set of reactive power compensation system by studying the development of the key technology and equipment of reactive power compensation,which is applied to the integrated power distribution cabinet of the distribution transformer for testing and obtained good test results.The main work is summarized as follows:(1)Through a lot of reading related literature on reactive power compensation,understand the technical development and trend of reactive power compensation,and be familiar with the advantages and disadvantages of various types of reactive power compensation equipment.Aiming at the pain points of large demand,high cost,low benefit and complex wiring for the application of reactive power compensation system in Chinese enterprises,a set of integrated reactive power compensation control system scheme was designed based on the principle of thyristor switching capacitor,in which the lower computer centrally executed the control command and the upper computer centrally issued the control command.(2)Through the analysis and simulation of the transient electrical parameter changes of the capacitor switching in reactive power compensation,two principles that the capacitor switching should follow are clarified: the capacitor must be discharged again after a long enough discharge time(3～5 minutes),and the thyristor is triggered at the zero-crossing point of the power supply voltage,and two engineering design attention points are clarified: the zerocrossing detection circuit should detect the voltage zero-crossing point at both ends of the thyristor,and a resistor with appropriate parameters should be connected in series with the capacitor compensation branch to eliminate the oscillation component at the moment of switching.These measures provide a theoretical basis for the implementation of the program.(3)The hardware and software of the capacitor switching execution system(lower computer)and the main controller system(upper computer)are designed and implemented respectively.The hardware design of the lower computer mainly includes composite switches and zero-crossing detection and trigger circuits.At the same time,the hardware system is designed with anti-interference measures,and the control program of the lower computer’s switching sequence of the composite switch is written in C language.The hardware design of the host computer includes the selection of sensor groups,the selection and design of data storage modules and communication modules,and the program of the main controller from collecting electrical parameters to issuing switching control commands is written in C language,and the program is realized at the same time real-time capacity detection and display,recording alarm information and operating information.(4)Finally,the system is installed in the integrated power distribution cabinet of the distribution transformer,and the inductive reactive power and power resistance cabinet are used to simulate the input of inductive reactive power to test the reactive power compensation effect of the system in the real environment.The test results show that the power factor has been effectively improved,and other functions are normal,with performance for further testing or application.