Research And Implementation Of Generalized Reactive Power Compensation Technology In Distribution Network

The distribution network system is directly oriented to the terminal user. It is an important infrastructure for people's livelihood and the important node of clean energy connected to distribution network in the future, and it is of great significance to carry and promote the national "Internet ?, intelligent energy strategy. At present, the three-phase load unbalanced and reactive unbalanced problems caused by the unreasonable spatial-temporal distribution of single-phase large-capacity load and the increase of inductive load are two major problems affecting the economic operation of the distribution network. To solve these problems,combined with the characteristics of using three-phase four-wire power supply and grounding and non-ground load coexistence in distribution network, with TSC (thyristor switching capacitor) branch as the basic compensation structure, the symmetrical component method is used to study and realize generalized reactive compensation technology of distribution network .The main research work and conclusions are as follows.The composition and characteristic of the distribution network was introduced briefly,and the causes and harms of reactive power and three-phase unbalanced in the distribution network was analyzed. Then combined with the governance situation of reactive power compensation and unbalanced in distribution network, generalized reactive power compensation technology was proposed to comprehensive control reactive power and three-phase unbalanced load of the distribution network.Based on the analysis of the structure and reactive power compensation principle of single-phase TSC , the single-phase TSC was used as the basic branch to study the structure of the main circuit of the generalized reactive power compensation device in the distribution network, then the combination of compensation circuit and Y compensation circuit was adopted. On the basis, the TSC main circuit was researched and designed. The Binay grouping method was chosen as arrangement of the capacitor. The optimal input threshold coefficient and the cutoff threshold coefficient of Capacitor was 0.6, and the capacitor switching time was chosen as the thyristor voltage across the zero.Based on the study of three generalized reactive power compensation algorithms , the generalized reactive power compensation algorithm based on the symmetric component method was selected in combination with the main circuit structure of the compensation device.According to the characteristics that there was only the positive sequence active current after the compensation system and the structure of main circuit,the generalized reactive power dynamic compensation model was built, according to this model, only need to measure the three-phase active power and reactive power of distribution network system can be obtained the capacity of the compensation capacitor in the main circuit. The simulink simulation was carried out to verify the correctness of TSC main circuit structure and generalized reactive power compensation algorithm. The simulation result shows that the reactive power and three - phase unbalance can be well compensated when using this structure and algorithm.With dsPIC30F6014A and CPLD as the core ,the hardware circuit design and software programming of control system of the distribution network reactive power compensation device was completed. The collection of electrical parameters of distribution network system and the control and protection function of the main circuit was realized. Combined with the idea of engineering and practical, experiment was carried out to verify the function of the designed generalized reactive power compensation device of distribution network. The experimental results show that the generalized reactive power compensation technology in the distribution network can accurately compensate the reactive power and three phase unbalance of the distribution network system.