直流偏磁对三相电力变压器的影响  

Influence on Three-Phase Power Transformer by DC Bias Excitation

作　　者：李泓志[1] 崔翔[1] 刘东升[2] 卢铁兵[1] 程志光[2] 

机构地区：[1]华北电力大学电气与电子工程学院,北京102206 [2]保定天威集团有限公司,保定071056

出　　处：《电工技术学报》2010年第5期88-96,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(50677016)

摘　　要：为了研究直流偏磁对电力变压器运行性能的影响,基于改进的变压器直流偏磁电路-磁路耦合模型,考虑铁心材料的涡流效应,定量分析了不同铁心形式和绕组联结的电力变压器产品直流偏磁下的励磁特性、漏磁特性、二次感应电动势特性和心柱直流偏置特性。通过定义变压器的直流偏置系数,统一评估了不同产品的耐受直流偏磁能力。分析结果表明,变压器直流偏置水平的升高使励磁电流波形畸变,谐波含量增加;绕组外漏磁加剧;同时二次感应电动势保持不变。三相三柱式铁心变压器受直流偏置的影响最小,而YN,yn联结单相三柱变压器组受直流偏置的影响最大。三角形联结绕组的存在对提高变压器的直流偏磁耐受能力具有积极意义。In order to look into the influence on the operation performance of a power transformer caused by the direct current（DC） bias,an improved electric and magnetic circuit coupled model is used.The eddy current effects of the core material are taken into consideration.The characteristics of exciting currents,leakage magnetic flux,secondary-side induced voltage,and the level of DC flux in limb are investigated for transformers with different core types and coil connections.The definition of transformer DC bias ratio is presented in the paper,with the aim of assessing the DC bias endurance in an unifed condition.The results indicate that the increasement of the DC bias ratio lead to distortion of the exciting currents waveform,increased harmonic currents and leakage magnetic flux from the coil.Meanwhile,the secondary-side induced voltage remains the same as in normal condition.In all transformer products,the three-phase three-limb transformer has the lowest level of sensitivity to the DC bias,but the single-phase three-limb tranformer bank with YN,yn connected coils has the highest level.The existence of the delta-connected coil has a positive meaning on improving the transformer endurance to the DC bias.

关 键 词：变压器 直流偏磁 磁路 励磁电流 漏磁 

分 类 号：TM14[电气工程—电工理论与新技术] TM41