摘要
通过分析汽轮发电机励磁绕组的磁动势分布建立了磁动势的数学模型,通过分析转子匝间短路引起的励磁磁动势分布变化情况,提出将短路后的励磁绕组磁势看作短路前的励磁绕组磁势和短路匝通过反向励磁电流产生的磁势的叠加量,由于前者是完全对称的,可只对短路匝产生的反向磁势进行分析。通过傅里叶分解得到了各次谐波分量,在考虑气隙偏心的情况下得到了定子感应电势,理论推导证明偏心对定子绕组感应电动势并不产生影响。定子三相对称电流合成了新的旋转磁动势,并在定子和转子绕组中形成感应谐波,其特征频谱不同于正常运行情况下的频谱。实验验证了文中理论分析的正确性和有效性。
By means of analyzing the distribution of magnetic motive force （MMF） of exciting winding of turbo-generator the mathematical model of MMF is established. Through the analysis on distribution variation of exciting MMF caused by inter-turn short circuit of rotor winding, it is proposed to regard the MMF of exciting winding after the short circuit fault as the superposition of the exciting winding MMF before the fault and the MMF produced by reverse exciting current in short-circuited turns, because the former is fully symmetrical, so only the reverse MMF produced by short-circuited turns is to be analyzed. By means of Furrier decomposition the harmonic components in various orders are obtained, and then the induced electromotive force （EMF） in stator winding is obtained when the air gap eccentricity of turbo-generator is taken into consideration. Theoretical deduction proves that the induced EMF in stator winding is independent of the air gap eccentricity of turbo-generator. The three-phase symmetrical currents in stator winding produce a new revolving MMF, then induces harmonics in rotor windings whose characteristic spectrum differs from that in normal conditions. The theory analysis of this paper is validated by experiments and according to the characteristic spectrum produced by introduced harmonics the inter-turn short circuit fault of rotor winding can be diagnosed.
出处
《电网技术》
EI
CSCD
北大核心
2008年第13期30-34,共5页
Power System Technology
基金
国家自然科学基金资助项目(50677017)~~
关键词
汽轮发电机
匝间短路
磁动势
谐波检测
turbo-generator
inter-turn short circuit magnetic motive force
harmonics detection
