高压架空导线电流与轴向温度关系模型及其参数变化规律研究

The effect of high voltage transmission line temperature on the power system has received extensive attention. However, since the present current-temperature relationship model for overhead conductor cannot be used to describe axial temperature distribution of conductor, it is hardly to obtain real thermal dynamic characteristics of transmission line in the actual engineering. By the basis of preliminary works, this project is armed to study the current-axial temperature relationship model and relevant parameters variation for overhead conductor. The first step in our study is using finite element analysis, thermoelectricity analogy theory and proposed micro-element thermal circuit modeling theory, to explore the micro-element thermal circuit structure of conductor with the splicing fittings and rupture. The relationship between current and axial temperature of conductor will be established accurately by building the micro-element thermal circuit model in the nonlinear state space. Then, to extract parameters in the micro-element thermal circuit model, a modified parameter identification method will be proposed by using nonlinear characteristic of temperature rise and causal characteristic of thermal circuit model. Moreover, the nonlinear objective function and the relevant optimization algorithm will be proposed and discussed, respectively. Finally, a experimental platform will be set up for axial conductor temperature measurement. Combined experimental data, parameter identification and correlation analyses, the influence mechanism of model parameters on the load current, weather conditions, splicing fittings and conductor rupture will be revealed. The change law model of parameters will be established based on the artificial intelligence algorithm. This study is intended to provide theoretic support and guidance for future development of high voltage power transmission technology, power system analysis and dispatching theory. This project also has the characteristics of urgency and prospection.

高压输电线路温度对电力系统的影响被广泛关注，但当前架空导线的电流与温度关系模型无法描述导线轴向温度分布，难以真实反映线路温度特性。本项目将基于前期工作，进一步研究导线电流与轴向温度关系模型及其参数变化规律。首先，以所提裸导线微元热路建模思想为核心，结合有限元分析和热电类比理论，探索计及接续金具和断股损伤的导线微元热路结构，构建基于非线性状态空间的微元热路模型，准确建立导线电流与轴向温度关系；再次，利用温升非线性特性和模型输入输出因果关系特性，改进微元热路模型参数辨识方法，提出非线性辨识目标函数，探索优化求解算法；最后，设计导线轴向温升实验平台，结合参数辨识和相关性分析，揭示负荷电流、环境气象、接续金具结构及压接压力、断股数及断股长度等因素对模型参数的影响机理，并通过人工智能算法建立参数变化规律模型。研究可为高压输电技术、电力系统分析及调度理论发展提供必要支撑和依据，具有一定前瞻性和迫切性。

本项目开展了架空导线的电流与轴向温度关系模型研究。首先，以微元热路建模思想为核心，结合热电类比理论，提出了裸导线、含有接续金具和计及断股损伤的导线微元热路结构，构建了基于非线性状态空间的微元热路模型；随后，提出了微元热路模型参数的非线性辨识方法，构造了参数辨识的非线性目标函数，并通过遗传算法和内点优化方法获得了模型参数的辨识结果；再次，设计了导线轴向温升实验平台，结合参数辨识和相关性分析，揭示了电流、环境气象、接续金具结构及压接压力、断股数及断股长度等因素对模型参数的影响机理，并分析了模型参数受户外气象影响的随机变化特性。最后，将所提微元热路模型应用于电力系统调度、电网重构、线路运行风险评估和电力设备功率半导体器件热管理等领域中。研究结果表明，所提导线电流与轴向温度关系的微元热路模型，克服了现有电流与轴向温度关系模型不能有效描述线路温度分布的不足。所提导线热参数辨识方法，有效解决了微元热路模型参数难以理论计算的问题。此外，相关实验平台揭示了模型热参数在不同环境条件下的变化规律，提升了导线电流与轴向温度关系计算精度。因此，所提微元热路模型能够为线路运行状态监测和风险评估提供依据，并为电热协调下电力系统分析和调度的发展提供基础，还可为电力设备中功率器件温度估计提供新的思路，具有重要的学术价值和应用价值。