阻抗分解法及其在无砟轨道阻抗求解中的应用  

Impedance Decomposition Method and Its Application in Calculating the Impedance of Ballastless Track

作　　者：张汉花 邹军[1] 王智新[2] 阳晋[2] 乔志超[2] 

机构地区：[1]清华大学电机工程与应用电子技术系,北京100084 [2]北京全路通信信号研究设计院,北京100073

出　　处：《电工技术学报》2017年第12期164-170,共7页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目资助(51577103)

摘　　要：轨道电路广泛应用于高速铁路控制系统,轨道阻抗是轨道电路设计中的重要参数之一。采用有限元法求解无砟轨道阻抗,其求解属于三维开域问题;同时考虑到导体趋肤效应,直接采用有限元分析时,存在模型剖分规模巨大、求解收敛困难等。为解决上述问题,提出了阻抗分解的方法,将无砟轨道阻抗分解为内阻抗和外阻抗,其中内阻抗利用无钢筋的二维有限元模型求解,外阻抗利用钢轨电流均匀分布的三维有限元模型求解。由此避免了同时对多个小尺寸单元的剖分,降低了剖分规模。以位于大地上方的单根导体阻抗的求解为例,分别采用阻抗分解法及解析法计算导体阻抗,两者计算结果相对误差小于2.5%,从而验证了阻抗分解法的正确性。应用阻抗分解法计算了山西中南部铁路双块式无砟轨道的阻抗,给出了该段无砟轨道在各频率下的阻抗取值范围。两组实测数据随频率变化趋势与计算结果一致,且符合阻抗变化范围。Track signal circuit has been widely used in the railway control system to detect the presence of a train. The track impedance is one of the most important parameters in designing the track signal circuit. To this end, finite element method （FEM） could be a good choice due to its capacity of handling complex geometries and media. If FEM is adopted, the open boundary problems in 3D must be tackled in the first place, because the ballastless track locates in an air-ground half space. Second, if the skin effect of conductor is included, the size of each element has to be less than the skin depth, which results in a huge number of unknowns. Accordingly, the computational time and the convergence problem would be big obstacles in reality. Thus, an impedance decomposition approach is proposed in virtue of the physical nature of impedance computation. The track impedance is decomposed into two parts, i.e., the inner and external track impedance. Each kind of impedance is calculated using an appropriate method, which can essentially reduce the computational burden. To validate the proposed decomposition approach, the impedance of a single conductor above the ground is taken as an example, and is calculated by the decomposition method and analytical formulation respectively. The calculated results agree with each other very well. The proposed decomposition approach is applied to calculate the impedance of the double-block ballastless track in Southern Shanxi railway. The frequency- dependent characteristic of the impedance is presented. The absolute value and the trend of the numerical results can reach agreement with the measurements if the certain error is considered from viewpoint of the practical engineering.

关 键 词：高速铁路 无砟轨道 有限元 轨道阻抗 

分 类 号：TM15[电气工程—电工理论与新技术]