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Research On The Intelligent Technology Of Low Voltage Control And Protective Switching Devices

Posted on:2012-11-01Degree:DoctorType:Dissertation
Country:ChinaCandidate:G H BaoFull Text:PDF
GTID:1262330422950409Subject:Motor and electrical appliances
Abstract/Summary:PDF Full Text Request
Smart grid is the latest and development trends of the world’s power systemdevelopment evolution. Intelligent electrical apparatus is a very important part of the smartgrid. The construction of the smart grid is bound to lead the development of the intelligentelectrical apparatus.In order to improve the intelligent technology level of low voltage electrical apparatusand meet the requirements of smart grid, the intelligent technology of AC contactors,motor protection, control and protective integrated switching devices (CPIS) are studieddeeply in this paper, so as to make a positive contribution to enhance the intelligent levelfor low voltage electrical apparatus.This dissertation mainly contains the following aspects:1) From the point of view of the research significance and background, this paperintroduces the concept and characteristics of smart grid. The relationship between smartgrid and intelligent electrical apparatus is presented in detail. The research situation aboutCPS, intelligent optimization design technology, and dynamic testing technology aresummed up from three aspects of intelligent control, intelligent protection, intelligentcontrol and protection integration respectively.2) After comparing the advantages of the different electromagnetic systemoptimization methods, the artificial fish swarm optimization algorithm based on geneticalgorithm is used in the low-voltage electromagnetic system optimization design. Thegeneral feature, calculation ideas, calculation method and the application of the algorithmis presented in detail. The new algorithm is applied to the optimization design of all kindsof electromagnetic appliances and good results are obtained. It lays the foundation forvarious appliances to achieve the appropriate basis functions.3) The paper investigates the image processing technology thoroughly that electricalapparatus dynamic characteristics testing device based on. The improvement methods ofthe image processing technology are proposed to improve the utilization efficiency oftesting device. The electrical apparatus dynamic testing technology and process based onabove method are elaborated as well as the image processing procedure, method and theattention matters. The dynamic characteristics of all kinds of appliances designed in thispaper are tested with the test device, and the feasibility of optimization design is verified.4) The new ideas of intelligent technology for electrical apparatus with the function of intelligent design, operation and measurement to adapt the unified strong smart grid areproposed. The researches realize the key technology of AC contactor including intelligentoptimization design, stable and reliable zero-current break, first open phase’s zero-voltageclose, state detection and fault diagnosis, life prediction, saving energy, communicationsand accurate measurement of dynamic characteristic, etc. As a result, the research level ofAC contactor intelligent is improved significantly.The principle of zero-current break and the cause of break failure are analyzed in thispaper. The intelligent optimization algorithm is used for the optimized design ofelectromagnetic motion mechanism to realize the rapid release. It can reduce the impact ofmechanical disparity on accuracy and stability of the zero-current break of three-phasecontactor, especially the first open phase contact, so that the reliability of zero-currentbreak is improved. Consequently, the AC contactor intelligent research level is improvedremarkably.The technical scheme of split-phase intelligent AC contactor is put forward in thisthesis. The compare and analysis of intelligent AC contactor with three-phaseasynchronous contactor and split-phase intelligent ac contactor is made also.5) The intelligent optimization design method is used to design and analyze deeply theelectromagnetic system of inclined surface iron core. After the thorough calculation andanalysis of suction characteristics between flat and inclined surface iron core in differentangles, the structure scheme of intelligent AC contactor with inclined face is put forward.The coil and core volume of intelligent inclined surface AC contactor can be saved greatly.Its dynamic characteristics are better and the reliability and stability of zero-current breakare higher. The new scheme has superiority and it will provide the foundation for theinclined surface core extremely extensive application in the future.6) The composition of intelligent motor control and protection appliance is introducedas well as the present situation of motor protecting technology. The intelligent motorprotecting technology and the development of intelligent motor control and protectionappliance are discussed intensively, and the intelligent motor protector product isdeveloped.7) The integrated electrical apparatus physical model of split-phase intelligent controland protection is proposed, which is based on fast electromagnetic repulsion mechanismand takes the contactor with the double-break and bridge contact structure system as themain body. This appliance model realizes the function and structure integration ofcontactor operation frequently, motor protection and short circuit fault protection. This dissertation highlights the calculation methods for electromotive repulsion incontactor system and fast repulsion driver, and carried on the simulation the repulsionforce under the short-circuit fault condition. Based on the short-circuit fault early detectioncombining current morphological wavelet with power supply voltage gradient, thedisplacement characteristics of movable contact affected by a combination of mechanicalforce and electromagnetic force under the conditions of different short-circuit current anddifferent parameters are simulated and analyzed. As a result, the mathematical models ofcontactor with short-circuit fault quick action and current limiting combined withmechanical and electromagnetic principle is established on the basis of the physical model.This mathematical models are based on short-circuit fault early detection technology of thecurrent morphological wavelet combined with power supply voltage gradient and fastelectromagnetic repulsion mechanism.The simulation research shows that the integrated electrical apparatus technology ofintelligent control and protection has excellent current limiting characteristic. It will set upthe theory foundation for developing integrated intelligent control and protection electricalapparatus with high performance.
Keywords/Search Tags:low voltage control and protective switching devices, Intelligent technology, AFSA based on geneticalgorithm, inclined surface, fast electromagneticrepulsion mechanism
PDF Full Text Request
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