Research On Dynamic Voltage Fluctuating Compensator Based On Instantaneous Reactive Power Theory

With the rapid development of economy, China's electricity load increase year by year. The impact, nonlinear load is increasing rapidly, the power system is developing into high voltage, long-distance transmission grid, and these bring new problems to the safe operation of the power system. Waveform distortion and grid voltage drop occurs frequently; all these problems put forward higher requirements for the power quality.This paper focused on dynamic voltage fluctuation compensator. Detailed research work has been done in the aspects such as DVFC modeling and parameters selection, control algorithm based on instantaneous reactive power theory and EMTP simulation .etc. Main work is as follows:(1)Situation analysisWith the high-speed development of national economy and the people's living standards rising, the social demand for power is expanding constantly; the voltage drop became one of the important aspects of power quality for concern. Detailed comparison of different measures adopted to improve voltage stability is made in this paper. According to the deficiency of the traditional equipment, researches on new equipment are needed. This paper put forward the dynamic voltage fluctuation compensator. This new device has many advantages and characteristics.(2)DVFC modeling and parameters selectionStudy the mechanism of the DVFC. This paper designed the structure of DVFC, and put forward single-phase and three-phase converter topology, established basic circuit models. At the same time, according to the theoretical analysis, the simulation research, and experience guidance, parameters of all parts of the main circuit, including the dc bus (dc capacitor), the buffer absorbing circuit, the charging circuit loop, the output reactor, the filter circuit and the cooling system. Lay the foundation for the future research.(3)Research on control algorithm based on instantaneous reactive power theoryAccording to the mechanism of compensate and control, the feature information can be obtained by calculation to realize the algorithm. This paper put forward the active current detection algorithm based on DC voltage control and the reactive current and harmonic detection algorithm based on instantaneous reactive power theory. Furthermore, the integrated control algorithm is obtained.(4) EMTP simulationThis paper built DVFC models by EMTP software, and then performed meticulous simulation calculation on them. For single-phase DVFC, detailed analysis and calculation is performed on the aspects such as DC voltage control, reactive power compensation, harmonic suppression and voltage drop compensation. For three-phase DVFC , the simulation is mainly about control algorithm's control effects on unbalanced load with harmonic. The simulation shows that the design for DVFC's hardware and software is successful.