The Approach Of Synthetic Control For Low-voltage Distribution Power Quality And System Research

Power is playing an increasingly important role in modern society. The power quality of a power supply system is required to be higher and higher due to the increasing improvement of the precision of power users’ equipment. Currently, that both the non-linear load and the impact load grow continiously, especially the wide use of power and electronic devices, has seriously affected the power quality of power supply system. Traditional power quality control approaches focus on one single indicator only to improve existing algorithms. In this thesis, the top three indicators (reactive pwoer, three-phase unbalance and harmonics) in low voltage distribution network are taken into great consideration, and a power quality control approach in low voltage distribution based on dynamic fuzzy nerual network is proposed owing to the result of analysis on these indicators mentioned above. This approach is varified to effectively imporve the power quality in low voltage distribution network.Firstly, the instantaneous reactive power algorithm, symmetrical component approach, and Fast Fourier Transform (FFT) approach are used for simulation analysis on reactive power, unbalanced, and three-phase harmonic respectively. Seperated control strategies are proposed for each problem exposed in the simulation analysis.Secondly, aiming at the power quality problems stated above, in this thesis, TCR+FC SVC reactive power compensation is used for reactive power, grid voltage oriented vector transformation approach is used for three-phase unbalanced tuning up, and FC single-tuned filters and FC high-pass filter are used to suppress harmonics generated in the process of TCR input. Those three approaches effectively combined with the help of power quality control methods based on dynamic fuzzy neural network so that it solves the problem more efficiently. Simulation analysis verified its utility. Finally, in order to verify the utility of the power quality control approach in low-voltage distribution in practical applications, the whole control system is studied carefully including controllers, power distribution subsystem, SVC compensation subsystem, FC filter group and load subsystems,5parts totally. We introduced electrical schematics and arguments’ calculation of each part and detailed selection result of component is listed. The results of the experiments show that the control approach can make all the three indicators meet power quality standard under various types of unbalanced load.