Research And Application Of Hybrid Filter Technique Based On The Passive Power Filter And The Active Power Filter In The Power Quality Management In Pingxi Substation

Large number of non-linear and impactive devices used in our lives not only increase power grid's burden, but also cause serious pollution, which make power quality constant deteriorated. However, more and more loads make higher demands on power quality of power grid, so that the contradiction between decline of power quality in the power grid and the demands of user on supplied power quality increase is intensifying, and the problem of power quality is becoming one of the grim problems that people must face. It is being an important subject needed to solved urgently by electrotechnical fields at home and abroad that improving and ensuring power quality, in particular to make sure sensitive user's power quality.Shizuishan power supply bureau supply power to the sensitive user of Yinchuan city, and the majority of overall harmonic source loads is concentrated in the pingxi substation, therefore, the power quality of pingxi substation is the key that affects that of Shizuishan power supply bureau. The monitor data of power quality in pingxi substation is analyzed and the conclusion is got: the key of the power quality in pingxi substation is the problem of harmonic loads, and the key point to improve power quality is to reduce or eliminate the main harmonic so as to harmonic voltage and harmonic current index can correspond to national standard regulations. With the actual situation in pingxi substation, a project that using hybrid active power filter to manage harmonic is proposed, then the feasibility of the project is verified by simulation. At last, an advice used this project is applied to pingxi substation's harmonic management, and finally measured data further proved the correctness of this project. The paper mainly did following several tasks:①In the paper, the necessity of power quality management comprehensively is expounded, the concept mischief and the definition of every interference in the power quality are introduced, and the management of power quality in pingxi substation Shizuishan region is of great urgency is illustrated.②Then the situation of power quality in Shizuishan region and the serious harmonic problem in the grid are analyzed, and the conclusion that the main mission of the substation is to manage the power quality of its harmonic is concluded.Also the harmonic sources which led to serious harmonic pollution are introduced.③In the paper, a hybrid active power filter against the 5th,7th harmonic which is more serious in pingxi substation based on the demands on the filter efficiency and economy is designed, and it is verified that active power filter could almost filter the other harmonic after the passive filter (PF) filtered the 5th and the 7th harmonic, which not only increased the efficiency of the filter, but also induced the demand of filter's capacity that ensure the efficiency of the filter and the economy.④The author also analyzed the management of the power quality deeply and studied importantly the application of the hybrid active power filter in the pingxi, Shizuishan region and its efficiency. From the monitor data before and after the management we can see that the application of device used hybrid active power filter made the content of harmonic induced to below the national regulation, which managed the harmonic pollution and power quality of the pingxi substation effectively that verified the correctness of the subject.Finally the author summarized the fulll paper and prospected the development of the monitoring and the management of power quality in this substation.