A1-104 CIGRE 2012 Calculation of Electromagnetic Force on ...

Fig.10 The electromagnetic force distribution acting on damping windings under negative sequence operation <strong>of</strong>absolute damping systemIV. CONCLUSIONSThe mathematic model <strong>of</strong> electromagnetic force calculation <strong>of</strong> damping system is established in this paper, whichcombined large hydro-generator with Lorentz force method. Taking the 1000MW large hydro-generator as an example,the electromagnetic force distribution under rated operation and negative sequence operation condition wererespectively analyzed. The conclusions obtained were as follows:1) Along the rotation direction <strong>of</strong> the rotor, the electromagnetic force <strong>of</strong> the first damping winding (1 # dampingwinding) was significantly greater than the rest <strong>of</strong> the damping windings in rated operation and the radialelectromagnetic force was greater than the tangential electromagnetic force.2) Along the rotation direction <strong>of</strong> the rotor, the electromagnetic force <strong>of</strong> the last damping winding (9 # dampingwinding) was significantly greater than the rest <strong>of</strong> the damping windings under negative sequence operation.Meanwhile, the tangential magnetic force <strong>of</strong> the No.9 damping winding was greater than the radial electromagneticforce <strong>of</strong> the No.9 damping winding.3) When the absolute damping system was adopted, the electromagnetic force <strong>of</strong> the first damping winding (1 #damping winding) was significantly greater than the rest <strong>of</strong> the damping windings along the rotation direction <strong>of</strong> therotor. Meanwhile, the radial magnetic force <strong>of</strong> the No.1 damping winding was greater than the tangentialelectromagnetic force <strong>of</strong> the No.1 damping winding.4) Under the negative sequence operation <strong>of</strong> the generator, the radial electromagnetic force played more importantrole than the tangential magnetic force. Under the rated load operation, this otherness was inconspicuous.REFERENCES[1] Li Shufang. Yao Ruoping, and Gao Yougang. “A new method to determine the 3-D field andtransposition way <strong>of</strong> large generator[C],” Power Engineering Society 1999 Winter Meeting, Vol.2 , No.1,pp.9-12, 1999.[2] Johann Hal demand. “Transposition in stator bars <strong>of</strong> large turbogenerators[J],” IEEE Transactionson onenergy conversion, Vol.119, No.3, pp.553-560, 2004.[3] Nabeta S.I, Foggia A , Coulomb J-L , and Reyen,G . “A non-linear time-stepped finite-elementsimulation <strong>of</strong> a symmetricl short-circuit in a synchronous machine[J],” IEEE Trans on Magnetics,Vol.31, No.3, pp.2040-2043, 1995.[4] Sturgess J P,Zhu M,and Macdonald D Cl.“Finite-element simulation<strong>of</strong> a generator on load duringand after a three-phase fault[J],” IEEE Trans on EC,Vol.7, No.4, pp.787-793, 1992.[5] Sun Yuguang, Wang Xiangheng, Gui Lin, and Wang Weijian. “Transient calculation <strong>of</strong> stator’s internalfaults in synchronous generator using FEM coupled with multi-loop method[J],” Proceedings <strong>of</strong> theCSEE, Vol.24, No.1, pp.136-141, 2004. (in Chinese)[6] He Chenbing, Gu Yujiong, and Xing Cheng. “Coupled flexural and torsional vibrations analysis <strong>of</strong>turbine generator shaft systems caused by short circuit fault[J],” Proceedings <strong>of</strong> the CSEE,Vol.30, No.32,pp.84-90, 2010. (in Chinese)[7] Men Liang , Luo Yingli , and Liu Xia<strong>of</strong>ang , Yang Jinfu,Chi Yongbin . “A case study <strong>of</strong>electromagnetic force distribution on rotor core surface <strong>of</strong> turbo generator[J],” Proceedings <strong>of</strong> theCSEE,Vol.25, No.1, pp.81-86, 2005 .(in Chinese)[8] Li Zhiqiang,Luo Yingli,and Meng Liang.“The calculation <strong>of</strong> local magnetic force in turbogeneratorwith FEM based virtual work principle[J],” Proceedings <strong>of</strong> the CSEE, Vol.27, No.15, pp.47-52, 2006. (in Chinese)