外绝缘表面液滴吸附生长模型及诱发沿面放电闪络机理研究

With the rapid development of offshore power generation, it is urgent to enhance the operating reliability of coastal region power networks. From the viewpoint of potential influence of coastal meteorology on the electrical performance of outdoor insulators, the purpose of this project is to investigate the absorption and growth modeling of water droplets and their effects on the process and mechanism of surface discharges on outdoor insulator. Based on the established experimental system for artificial simulation of atmospheric conditions, by using the methods of experimental investigation, theoretic analysis and numerical simulation, the first step is to investigate the absorption, nucleation, growth, coalescence, distribution characteristics and heat transfer mechanism of water droplets on the insulator surface. Following this, the modeling of heat transfer density and dropwise condensation can be established to obtain both static and dynamic distributions, the droplet size and related influencing factors. Then, by using simultaneous detecting techniques of discharge current and discharge light, both electrical and luminous characteristics can be obtained during the process of inception and propagation of streamer discharge and arcing formation affected by the varying parameters of water droplets. The characteristic parameters of surface discharges include discharge inception, path and velocity of discharge propagation, discharge patterns, discharge intensities (discharge energy and luminous intensity of discharge light) and arcing parameters (arcing radii, propagating length, distribution and dynamic alternation). The parameters of water droplets considered in this project are droplet type, droplet size, PH level, absorption amounts and distributing characteristics. Thus, the variation tendency and relationship between the discharge characteristics and the water droplet parameters can be obtained. After these, the simulation and calculation will be carried out by using finite element method to analyze the charge and size effects of water droplets on the potential distribution and the electric field distortion on the insulator surface. Finally, both the theoretical analysis and simulation model can be obtained for streamer discharge and arcing formation induced by water droplets. Therefore, the influencing factors and mechanism can be investigated to reveal the process and transition of streamer discharge inception, propagation and arcing formation. The research results and experimental system founded in this project will be useful to the investigation on surface discharge mechanism of outdoor insulator in coastal regions, which can further be helpful to enhance the operating reliability of coastal region power networks.

海上风电规模不断扩大对沿海地区电网运行可靠性的要求日益提高。本课题以探索沿海电网外绝缘表面液滴吸附生长模型及诱发沿面放电闪络机理为研究目标，采用实验研究、理论分析和数值模拟相结合的方法研究外绝缘表面液滴吸附、成核、生长、合并、分布特征与传热机理，建立外绝缘表面热流密度与滴状凝结模型，获取液滴静态与动态特征函数及宏微观影响因素；采用放电电流与放电光学同步检测技术获取液滴静态与动态参数下外绝缘表面流注起始、发展以及电弧形成过程中电、光特征量，建立液滴参数（类型、尺寸、酸碱度、吸附量、分布特征）对放电起始、发展路径与发展速度、放电图谱、放电强度（能量与光强）以及电弧特征（直径、长度、分布与动态交替）的影响规律；基于有限元仿真计算分析液滴静态与动态参数对表面电位分布与电场畸变的影响，揭示液滴诱发外绝缘沿面放电起始、发展与转换机理，为提升沿海地区电网外绝缘运行可靠性奠定理论与实验基础。

针对海上发电规模不断扩大对沿海地区电网运行可靠性的要求日益提高，项目建立了沿海电网外绝缘表面液滴吸附生长模型及诱发沿面放电闪络的建模仿真与实验测量系统与方法，研究了外绝缘（硅橡胶和陶瓷绝缘子）表面液滴吸附、成核、生长、合并、分布特征与传热机理，获取了不同液滴参数（体积和电导率）、表面张力、接触角和施加电压对液滴静态、动态特征和表面电场最大值的影响规律，基于搭建的放电电流与放电光学同步检测技术获取了液滴参数（类型、尺寸、酸碱度、吸附量、分布特征）对放电起始、发展路径与发展速度、放电图谱、放电强度（能量与光强）以及电弧特征（直径、长度、分布与动态交替）的影响规律，揭示了外绝缘表面液滴吸附凝结及其诱发外绝缘沿面放电和闪络的机理，为提升沿海地区电网外绝缘运行可靠性奠定理论与实验基础。