特高压变压器直流偏磁对绕组电流的影响  

Research on Winding Current of UHV Transformer under DC-Bias

作　　者：李冰 王泽忠[1] 刘恪 杨箫箫 李明洋 Li Bing;Wang Zezhong;Liu Ke;Yang Xiaoxiao;Li Mingyang(Beijing Key Laboratory of High Voltage&EMC North China Electric Power University,Beijing 102206 China)

机构地区：[1]高电压与电磁兼容北京市重点实验室(华北电力大学),北京102206

出　　处：《电工技术学报》2020年第7期1422-1431,共10页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划(2016YFC0800100);中央高校基本科研业务费专项资金(2019QN105)资助项目。

摘　　要：为了快速而准确地分析特高压变压器负载下直流偏磁对各绕组电流的影响,基于棱边有限元法建立特高压变压器的时域场路耦合模型,在磁场模型中根据能量扰动原理,通过能量增量计算动态电感,在电路模型中利用动态电感参数建立瞬态电路偏微分方程模型并应用四阶龙格库塔法进行求解。针对特高压变压器大电感、小电阻带来的极为漫长的过渡过程以及直流偏磁计算易被忽略的难点,通过在电路模型中增加串联电阻,使达到稳态的时间大大缩短,并通过电压迭代补偿,有效消除串联电阻值导致的计算偏差,计算特高压变压器负载运行时受直流偏磁影响下的励磁电流与各绕组电流,并分析不同直流偏置电流对特高压变压器各绕组电流的影响。通过搭建与特高压变压器相同的铁心结构以及高、中、低压侧具备相同绕组匝数比和容量关系的缩比模型直流偏磁试验平台,验证了该文所提模型的正确性。To analyze the DC bias effects on winding current of ultra-high voltage(UHV) transformer with high accuracy and reduced transient process, the field-circuit coupling model of UHV transformer is established based on the edge finite element method. In the magnetic field model, the dynamic inductance is calculated according to the energy increment principle according to the energy disturbance principle. The transient partial differential equation model of circuit is established by using the dynamic inductance parameters in the circuit model and solved by the fourth-order Runge-Kutta method. Due to the characteristic of large inductance to small resistance in UHV autotransformer, which can easily lead to not only a long transient process but also the inundation of the small DC voltage relative to the 1000 kV AC voltage during the iterati ve calculation. By adding series resistance in the circuit model, the transient process is greatly shortened, and the calculation deviation caused by increasing series resistance value is effectively eliminated by voltage iterative compensation. The excitation currents and winding currents of UHV transformer under the influence of DC bias are calculated, and the influence of different DC bias currents on the windings of UHV transformer is also analyzed. The correctness of the model is verified by a scale-reduced transformer.

关 键 词：特高压变压器 直流偏磁 棱边有限元场路耦合模型 串联电阻 电压补偿 负载运行 缩比模型 

分 类 号：TM153[电气工程—电工理论与新技术] TM41