The Study On Comprehensive Compensation Of Harmonic And Reactive In The Distribution System Of Intelligent Buildings

Nowadays, it is a domestic and international research focus that the intelligent buildings technology and the harmonic suppression technology. As to the hazard, the harmful effects and comprehensive treatment problems of harmonic and reactive of intelligent buildings, many scholars have noticed, but they have not thought much of it. This article studies a new method of comprehensive treatment from the theory and technology and finds the new solution just to the subject of harmonic and reactive compensation in distribution system of intelligent buildings. The paper studies a new method of comprehensive treatment in the theory and technology, seeks a new way to solve, and makes a series of meaningful achievement in research(1) By studying and analyzing the load of intelligent buildings, the paper gives the main characteristics of the load, and points out the reason, hazard and harmful effects of harmonic and reactive; At the same time this paper summarizes the actuality of harmonic suppression and reactive compensation and comprehensive treatment of harmonic and reactive in power supply and distribution system, and points out the problems existing; Especially, it for the first time proposes a new method of comprehensive treating harmonic and reactive of intelligent buildings by using the single-phase Unified Power Quality Conditioner (UPQC) . To improve quality of power supply of intelligent buildings and power supply reliability and to reduce such as power network pollution caused by harmonic resource of intelligent buildings of harmonic etc, the new method has very important meaning, and offers a new way for intelligent buildings harmonic and reactive compensation technology.(2) Through the generalization of the development history, research actuality and technology progression of the active power filter (APF), and classifying APF according to the voltage grade and speed of response, topology of circuit and compensating system parameters of it. After researching its application and analyzing its performance, this paper draws an important conclusion: for the system whose power is less than 100KVA, using the single-phase low powered APF is appropriate; for theunbalanced three-phase system, adopting three single-phase APF is more suitable than adopting a three-phase APF; and it will be more favorable to comprehensive compensate harmonic and reactive power with series-parallel connection APF. Combining the actuality of application and type choice of APF, the paper points out the problems needed to be solved in APF exploitation and application. The conclusion has directively meaning to APF exploitation and application.(3) The paper develops a new-type APF based on DSP consisting of a SAPF and a PAPF -single-phase UPQC, and the concept has been made out. Considering the design of the main circuit structure, the paper studies and demonstrates its composing principle and the hardware implementing scheme; The paper firstly points out that for the user terminal, this equipment can effectively compensate the fundamental wave of city electric supply, and prevent harmonic of city power supply from polluting the load; To the power network terminal, the equipment can effectively prevent the harmonic caused by the non-linear load from polluting power network, and compensate reactive and make the power factor close to 1. The paper theoretically proves that single-phase UPQC can dynamically suppress harmonic and compensate reactive, and points out the energy exchange mechanism among the city electric supply, UPQC and non-linear load. The paper not only proposes and designs single-phase UPQC, but also studies its application, all of which has innovative and enlightening meaning to the relevant theory of active power filter design and the technology of comprehensive treatment to harmonic and reactive in low-voltage distribution system.(4) Aiming at the detection to harmonic current and reactive current in series wound part of UPQC, two new methods to detect harmonic current and reactive current in the single-phase load cur...