用于特快速暂态仿真的大型电力变压器线圈频域分段建模  

Piecewise Frequency-domain Modeling of Large Power Transformer Windings for Very Fast Transient Overvoltage Simulations

作　　者：杨钰[1] 王赞基[1] 

机构地区：[1]电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084

出　　处：《中国电机工程学报》2010年第10期66-71,共6页Proceedings of the CSEE

基　　金：国家自然科学基金项目(50577034)~~

摘　　要：针对超高压和特高压电力变压器特快速暂态仿真的需要以及以线匝为单元的多传输线模型难以用于完整绕组的建模、在单一模型中难以在近10MHz频率范围内确定频率依赖参数的问题,提出了一种频域分段建模的方法。在低于4MHz频率范围内采用新型的集总参数RLC电路模型,在高于4MHz频率范围内采用无损多传输线(multitransmission line,MTL)电路模型进行建模,在保证求解准确度的基础上,比单纯采用MTL模型有效降低了求解的复杂度,因而可用于具有大量线匝的绕组的建模。在分段模型中,频率依赖的损耗参数和电感参数可以分别考虑,避免了在单一模型中确定这些参数的困难;同时,在所关心的10MHz以下频率范围内以100kHz,4MHz为2个分界点,从低频到高频分别采用1,10和50kHz3种分辨率求解频域方程,既提高了低频段求解精度,又减少了高频段计算时间。理论分析和实例仿真表明该方法适用于大型电力变压器特快速暂态仿真。A piecewise modeling method is proposed in this paper, to meet the need of very fast transient overvoltage （VFTO） simulations of large EHV and UHV power transformers and to overcome the challenges that it is difficult to apply the multi-transmission line （MTL） model to the whole winding and to determine the frequency-dependent parameters in a model within about 10MHz frequency. A new lumped RLC circuit model was applied in the frequency range below 4MHz, and the lossless MTL model was used in the range above that frequency. As a result, the complexity of calculation was greatly reduced and hence the proposed model can be used to model the winding with a large number of turns. In the model, the frequency-dependent losses and inductances were determined in the new RLC circuit and MTL model respectively. Besides, the concerned frequency range up to 10 MHz was divided into three sections with joint frequencies at 100kHz and 4MHz, in which the sampling rates were 1, 10 and 50kHz respectively so that not only the accuracy of the solutions at the low-frequency section can be improved, but also the computational time can be largely saved at the high- frequency section. The theoretical analysis and simulations showed that the proposed method is valid for the VFTO simulations of large power transformers.

关 键 词：特快速暂态过电压 电力变压器:仿真建模 集总参数电路 多传输线模型 

分 类 号：TM13[电气工程—电工理论与新技术] TM14