| With the advances of society and the development of science and technology, more and more strict requirement for power quality is needed by power users because of the problems caused by voltage quality and harmonics are becoming increasingly serious. But harmonics pollution of the power system is serious as the extensive application of electronic devices. the traditional reactive power compensation and filter method can’t satisfy user’s need,and has great affection to the electrical equipment in using time and precise running, how to use the active power filter to do harmonic suppression dynamically, providing reliable and good the power quality has become a major in harmonic suppression. therefore, it is imperative to promote the research process of harmonics suppression and reactive power compensation together by an integrated equipment in the power transmission and distribution system, it has become national strategy in national energy saving.Based on the project of harmonics suppression and reactive power compensation in35kV transitional power station in Guang Xi province, focusing on theory and application of high voltage hybrid active power filter,35kV hybrid active power filter and its running characteristics and adaptive control with frequency division and design parameters of the main circuit and dead-time effect and its compensation strategies are studied, then analyzing some key technology in the application of35kV hybrid active power filter. Some measures are put to these problems. The overall design of system is introduced detailed, the design and some work experience is also extended to other transitional power station, providing a useful reference for other appliction. The characteristics, innovation and beneficial conclusion of the project is introduced by this thesis as following.The advantage and disadvantage of traditional injection hybrid Active Power Filter(SRHAPF) is analyzed, the topology of a new series resonance injection hybrid active power filter was proposed, the basic principle and structure of the new hybrid35kV was analyzed, the compensation and stability was studied, and the traditional injection structure、the harmonic injection ability and avoiding enlarging harmonic in injection branch for SRHAPF has bigger superiority, SRHAPF can provide large has good robustness, not to be impacted by impedance in the grid and branch parameters in fundament, it has good effect suppression to equivalent impedance of the grid and series and shunt resonance branch filter with harmonic suppression and reactive power compensation, the research results shows SRHAPF has good stability by Routh.The composite control of active power filter is proposed in harmonic current detecting of the load and harmonic current of the grid, it can get a good load current of harmonic suppression, suppressing the resonance of passive power filter and the grid and improving the filtering capacity of passive power filters. The two control parameters of Ks and KL are decoupling completely by composite control method, which can require two independent control coefficients and obtain satisfactory effect. The delay of active power filter of digital control system is took into account, which will reduce compensation effect of the active power filter, even causing high harmonic amplify, making safe and reliable operation of the system get worse. An adaptive prediction method based on reference current of active power filter is presented by this thesis in order to reduce the delay of active power filter of digital control system. An adaptive prediction method based on reference current of active power filter has high accuracy and fast convergence; it can obtain accurately the desired results even if frequency or amplitude of the grid changes, A traditional fuzzy algorithm is regulated in the tracking error based on the ratio and integral coefficients(PI) of the total integral controller. Because of the nonlinear and randomness and strong disturbance of enterprises load, then the load current and harmonic amplitude change is not linear in proportion to the increase and decrease in any time, some change faster than others. Apparently, the parameters of this fuzzy uniform regulation on the compensation control of all the harmonics has blindness, then limiting to improve the traditional control algorithms effect.To get more perfect and increase the robustness of the control system, an improved neurons division frequency control in the grid is presented by this thesis,which can get frequency detection and control specific harmonics over the standard and use PI control respectively. The harmonic suppression dynamically of the hybrid active filter for is improved, the regulation of coupling between the harmonics is suppressed effectively.Whether the hybrid active power filter (HAPF) could or not get desirable harmonic suppression effect, it mainly depends on the optimal design of passive power filter (PPF). Taking a new injection type HAPF as an example, this thesis studies the design methods of PPFs in the proposed topology structure, presents general principles and gives some considerations on safety and reliability, and analyzes the arrangements of the three-phase reactor groups. The demonstration result in the engineering application verifies the above mentioned theory, and the harmonic suppression effect is remarkable. The methods for theoretical analysis and relative conclusions can be used as references for the design of PPF for other type of HAPF.Dead-time exists in the active power filters. By using the influence parameter of dead-time effect, this thesis carries on the quantitative simulation analysis of dead-time in fundamental component and harmonic domain. Combining the application experience, three methods of dead-time compensation are discussed in this thesis, including no dead time switch mode, novel current feedback dead time compensation method and dead time pre-compensation method. Simulation and experiment shows the efficiency of this method.Aimed at need of harmonics suppression and reactive power compensation of transitional power station,.Based on above chapters’theory,impedance of the grid system capacity、loading capacity distorted current and reactive power are analyzed combining engineering application, then the whole design device for harmonics suppression and reactive power compensation of transitional power station is given, simulations and application validates the effectiveness.focusing on application in engineering, the system designed and application simulations is given by this thesis, the structure and design for controller hardware and DSP software algorithm is given detailed,the design and some experience is also provided a useful reference to other energy quality and related equipment.According to above theory, Based on the project of harmonics suppression and reactive power compensation in35kV transitional power station in Guang Xi province, focusing on theory and apply high voltage hybrid Active Power Filter,35kV hybrid active power filter and its running characteristics and adaptive control with frequency division and design parameters of the main circuit and dead-time effect and its compensation strategies are studied,some key technology problems in the application of35kV hybrid active power filter is put. The overall design of system is introduced detailed, the technology and solutions showed it is reliable and good in the project. These research results can provide technical support for national policy implementation of energy saving and reducting emissions, it can also provide technical support for green grid and enterprises and transitional power station, the design and some work experience is also extended to other field, providing a useful reference for application of hybrid active power filter... |
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