Research On Magnetized Property Of Iron Core For Magnetically Saturated Controllable Reactor

The magnetic field of iron core for the magnetically saturated controllable reactor isexcited by the interaction of both direct current (dc) and alternating current (ac) and byusing different expression ways to describe the magnetized property of its iron core underdc bias, the simulation results for the magnetic field and loss of iron core will be different.In this paper, the magnetized property of iron core for the magnetically saturatedcontrollable reactor under dc bias was investigated in detail. On the basis of experimentalmeasurements of different magnetic properties of grain-oriented electrical steel sheet, thedefinition and description method of the magnetized property of iron core under dc biaswas studied. Taking a dry-type transformer model running under dc bias as an example, therightness of definition of magnetized property of iron core under dc bias was verified byusing simulation analysis and experimental test. At last, the research results mentionedabove were applied to analyze a800kV magnetically saturated controllable reactor product,and the magnetic field of iron core and current on line side were simulated. The detailedresearch contents are as follows:Firstly, the definition and description method of magnetization characteristics of ironcore under dc bias were studied. Based on Epstein frame test, the magnetization curves andloss curves were measured along rolling direction and perpendicular to the rolling directionof oriented electrical steel sheet under the different magnetization conditions. Thedescription methods of several magnetization curves such as ac magnetization curve, dcmagnetization curve, average magnetization curve, ac bias magnetization curve, andresultant magnetization curve of ac and dc were studied, and magnetization curvedescribing the magnetized property of iron core under dc bias was defined. Secondly, the experimental circuit which make two D-160/2type dry-typetransformer models operate under DC bias condition was designed and built, and itsno-load loss was tested. By using the Infolytica commercial software, thethree-dimensional finite element simulation model was established, and the difference ofno-load loss when applying different magnetization curves to silicon steel sheet oftransformer iron core was discussed. The comparison of experimental test results with thesimulation ones of iron core loss was analyzed, and the effectiveness of definition ofmagnetization property curve of iron core under dc bias above was verified.Finally, the dc biased magnetization curve of silicon steel sheet was applied to thesimulation analysis of magnetic field for a800kV magnetically saturated controllablereactor. The magnetic field and current on line side winding were computed with differentcontrolled currents, and compared with the experimental data provided by themanufacturer.