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物理模拟是研究电力系统特性、检验继电保护装置性能的模拟试验方法,可以真实地再现被研究对象的物理过程.对于长距离输电线路的物理模拟,如直流输电或半波长交流输电线路等,主要采用由Π型或T型电路级联构成的集总等效电路,级联电路的数目主要根据经验或仿真计算确定,缺乏一般的解析公式.该文提出了无损耗传输线物理模拟的集总等效定理,通过对无损耗传输线的空间离散并求解差分—微分方程,获得了Π型或T型电路的级联数目与传输线长度、最高频率、延迟时间及其相对误差的解析公式.采用该解析公式,可以根据物理模拟精度等实际需求,确定Π型或T型电路的数目.最后,以某1000kV三相半波长输电线路的物理模拟为例,仿真验证了文中集总等效定理的正确性.“,”The physical analogy method of power system is the most important test one to understand characteristic of power system and to check performance of relay and control devices, because it may really recurrence the system's physical process. In order to implement physical analogy of long-distance power transmission lines such as HVDC or half-wave length HVAC ones, in general, the equivalent lumped-circuits consisted of some chainedΠ-type or T-type circuits are used in laboratory. However, the chained number ofΠ-type or T-type circuits mainly was determined based on the researcher's experiences or numerical simulation of the transmission lines. The author had not found general formulae to determine the chained number in previous literatures up to now. In this paper, a lumped-circuits equivalent theorem for physical analogy of lossless transmission lines was proposed and the general formulae including chained number, length of transmission lines, the highest frequency, delay time and its relative error were obtained by means of discretization of the lossless transmission lines and solution of the difference- differential equation. The general formulae may be easily applied to determine the chained number ofΠ-type or T-type circuits according to required precision of physical analogy. Finally, the validity of the lumped-circuits equivalent theorem proposed in this paper was verified by numerical simulation of a 1000kV three-phase half-wave length transmission lines.