空间离子流作用下直流输电线路电磁暂态特性及仿真方法

HVDC transmission line is able to transmit large capacity to the far away. Its safety and reliability issues are particularly important. Electromagnetic transient overvoltage is an important cause of line fault. The ion flow field around the line has an important influence on the electromagnetic transient of the line. This project application focuses on the electromagnetic transient problem of HVDC transmission line under the action of space ion current. The dynamic coupling process between the space ions and the transient voltage of the conductor will be studied to obtain the space-time distribution of space ions in the transient state. The physical meaning of the capacitance and conductance of the DC transmission line under the action of the ion flow field and the calculation method of the corresponding parameters will be investigated. The dynamic coupling mechanism between the positive polarity space ions and the corona discharges under negative impulse voltage will be studied, and the characteristic of the corona discharges under impulse voltage on the DC transmission line will be analyzed. The charge and voltage characteristics of corona discharges under impulse voltage on actual conductor considering the effect of space charges will be obtained. Finally, the electromagnetic transient model and the corresponding numerical calculation method of the DC transmission line considering the ion flow field and the corona discharges under impulse voltage will be obtained. The study can not only provide powerful simulation tools for the analysis of overvoltage and insulation coordination, fault identification, and radio disturbance prediction of HVDC\UHVDC transmission line, but also can reveal the coupling mechanism between space ions and conductor transient voltage and corona discharges under impulse voltage. The research has theoretical significance and important engineering application value.

直流线路输送容量大、距离长，其安全可靠性问题尤为重要。电磁暂态过电压是造成线路故障的重要原因，直流线路空间离子流对线路电磁暂态有重要影响。课题针对空间离子流作用下直流输电线路电磁暂态问题，研究空间离子流与导线暂态电压之间的动态耦合过程，获得暂态下空间离子时空分布特性；研究空间离子流作用下线路电容和电导参数的物理意义，提出空间离子流作用下直流输电线路电容和电导参数的计算方法；研究正极性空间离子与导线负极性冲击电晕间的动态耦合机理，获得直流输电线路冲击电晕特征，获得考虑空间电荷影响的实际导线冲击电晕伏库特性；最终建立考虑空间离子流和冲击电晕的直流输电线路电磁暂态模型和相应的数值计算方法。研究不仅可以为超、特高压直流输电线路过电压和绝缘配合优化、故障识别、无线电干扰预测等提供有技术支撑，还可以揭示空间离子与导线暂态电压、冲击电晕之间的耦合机理，研究具有重要的理论意义和工程应用价值。

雷击冲击过电压是造成输电线路故障的重要原因，直流输电线路空间离子流对线路雷击过电压有重要影响。课题研究空间离子流作用下直流输电线路分布参数特性和冲击电晕特性，提出相应的电磁暂态仿真模型和计算方法，并应用于多重雷击下直流输电线路暂态过电压的分析，主要成果有：.推导出了空间电荷作用下考虑冲击电晕暂态过程的新型传输线方程，确定了空间电荷对传输线方程参数的影响机理，为分析冲击电晕特性以及过电压传输特性提供了理论依据。.设计了观测导线冲击电晕特性的电晕笼，搭建了直流和冲击联合加压试验平台，开展了直流离子流下冲击电晕特性试验，获得了不同直流和冲击极性组合下直流输电线路冲击电晕的伏库特性曲线，得到了不同空间电荷下的冲击电晕起始电压。.建立了考虑冲击电晕影响的离子流场暂态计算方法，明确了冲击电晕过程中空间电荷的迁移、复合演化发展过程，获得了空间电荷和直流导线冲击电晕的相互作用机理。.建立了求解空间电荷动态作用下非线性传输线方程的时域有限差分法，获得了存在空间电荷时直流输电线路在多重雷作用下的过电压传输特性，揭示了不同直流和冲击极性组合下冲击电晕对线路暂态过电压的影响机理。.课题不仅揭示了空间离子与线路暂态过电压、冲击电晕之间的耦合机理，还为超、特高压直流输电线路过电压和绝缘配合优化、故障识别等提供有力的仿真工具。课题共发表论文11篇，其中SCI论文10篇，国内核心期刊论文1篇，获国家发明专利3项，培养博士生一名。