现有电力线路分布参数模型与多节集中参数模型是分析高频暂态特性的主要模型,其模型结构复杂,计算量大;单节集中参数模型结构简单,但适用频段范围远低于分布参数模型的首谐振频段。为此,以单相均匀传输线线路末端开路、短路为例,分析了分布参数模型、单节П(T)、Г模型的阻抗特性,并根据各模型最低频段等效阻抗的误差分析结果,提出了单节集中参数模型参数计算方法,即以工频等效阻抗、最小(首)谐振频率相等,最低频段内等效电抗综合误差最小为原则,将单节П(T)、Г模型的适用频段范围提高到了分布参数模型的首谐振频率,扩大了其适用范围。算例结果验证了该方法的有效性。
Complicated structure and heavy calculation burden are defects of existing distributed parameter model and multiple lumped parameter models utilized for the analysis on high-frequency transient characteristics of transmission lines. The structure of single link models with lumped parameters is simple, however its applicable frequency band is far below the first resonant frequency band of distributed parameter model. For this reason, based on the cases of open-circuit and short-circuit at the end of single-phase uniform transmission line, impedance characteristics of the model with distributed parameters, the single-link H-shaped, T-shaped and F-shaped models with lumped parameters are analyzed, and according to the result of error analysis on equivalent impedance at the lowest frequency band of each model a method of parameter calculation for single link model with lumped parameters is proposed, namely based on the principle of ensuring power-frequency equivalent impedances equal, the first resonant frequency bands equal and comprehensive error of equivalent reactance within the lowest frequency band minimum, the applicable frequency band of single-link H-shaped, T-shaped and F-shaped models is raised to the first resonant frequency band of distributed parameter model, thus the applicable range of H-shaped, T-shaped and F-shaped models are extended. Simulation results show that the proposed method is effective and correct.