特高压输电用调相机动态工况约束下端部复杂系统内磁热演变机理研究

Ultra high voltage transmission system with the condenser is the major construction project for the electric power system. The research on the new generation of condenser has just started in our state, and the basic theory system is not perfect. For the technical requirements for practical applications of the condenser used for ultra high voltage transmission system, this project would carry out the research on the basic theory of interaction mechanism between the end region feature of the condenser and the behavior of electric power system with the grid voltage being changed and the depth phasing operation. Both the combined and multistage electromagnetic shielding systems and the exhaust-forced mixed cooling type used for the end region of condenser are proposed. Establishing the field-circuit-grid-control coupled model with the 3D complex structure of end region considering the closed loop control systems of excitation when the condenser used for extra-high voltage engineering is under the transient reactive compensation operation. A method that uses additional electrical vector potential instead of rotating DC excitation for analyzing the multiple physical fields is proposed. Calculating the flow resistance of the cooling medium in multi-channels of the end region based on the constitutive relation. Studying the evolution and equalization law of 3D dynamic distribution of leakage magnetic field, heat generation and stress of end structures under armature electrical quantities perturbation and excitation impulsion. Exploring the impacts of nonlinear multi-factors on the multi-field quantities of the end region of the condenser, and match strategy of the end structures. Completing the experimental verification. The design method of enhancing the service toughness of the end structures of the condenser under dynamic condition constraint would be formed, which provides the necessary theoretical support for the application of the condenser in the ultra high voltage transmission system.

以调相机为核心的特高压输电系统是当前电力系统的重要建设工程，我国新一代调相机的研究刚刚起步，基础理论体系不完善，本项目面向特高压输电用调相机实际应用的技术需求，开展电网电压突变和调相机深度调相运行时端部本体特征与电力系统行为相互影响机理的基础理论研究，提出调相机端部复合式及多级式电磁屏蔽系统和抽压混合通风冷却方式，建立计及特高压工程调相机瞬时无功补偿的励磁闭环控制系统的端部三维复杂结构下场-路-网-控耦合分析模型，提出附加动态矢量电位代替直流旋转磁势的端部多物理场分析方法，根据本构关系确定端部多流道冷却介质流动阻力，研究电枢电气量扰动和励磁瞬态冲击下调相机端部三维动态漏磁、发热和应力演变及均衡化规律，探索非线性因素对调相机端部多场量协同影响机理和端部结构匹配策略，完成实验验证，形成提升调相机动态工况约束下端部构件服役坚强性的设计方法，为大型调相机在特高压输电系统中的应用提供必要的理论基础。

特高压输电系统用大容量同步调相机具备响应快、工况灵活、瞬时无功支撑能力强等优势，可有力保障特高压输电系统电压平衡、频率稳定。在特高压交直流电网快速发展的背景下，本项目以世界首台300Mvar大容量空冷同步调相机为研究对象，针对新一代大容量同步调相机面临的科技问题开展了相关理论与实验研究，为解决特高压输电用大型同步调相机端部复杂结构下漏磁与发热问题提供了理论与实验参考。.本项目建立了大容量同步调相机端部区域三维瞬态电磁场数学模型，充分考虑了调相机端部磁饱和非线性、涡流效应和集肤效应等因素，探究了过励及欠励运行状态约束下调相机端部漏磁场变化规律，精准计算了端部结构件电磁损耗。此外，本项目提出了不同组合型式的调相机端部拓扑结构，对比研究了端部构件组合型式对调相机端区漏磁分布及构件涡流损耗的影响。.本项目建立了调相机端部复杂通风系统的流固耦合传热模型，研究了端部区域内冷却介质流态及各构件表面散热系数分布规律，进一步探究了调相机在过励与欠励运行状态约束下端部构件传热特性，掌握了调相机端部区域结构件最高温度漂移规律，明确揭示了端部结构型式、材料特性、冷却介质属性对端部域内流体流动状态及结构件热表征的影响机制。.为解决大容量同步调相机端部区域磁-热设计成本问题、提升大型调相机端部冷却系统设计实验的效率，本项目创新性的提出了数值分析与数据驱动相结合的精确预测大型同步调相机端部温升的方法，通过构建联级结构的DFPM模型，实现了精确预测冷却条件约束下调相机端部区域的流热特征，提升了调相机端部磁热综合设计效率。.本项目开展了300MVar空冷同步调相机端部冷却系统的温升测试实验，完成了调相机过励及欠励运行状态约束下端部铜屏蔽、定子边段铁芯、定子端部绕组绝缘的温度测试。本项目研究成果有望为解决特高压输电系统大型同步调相机端部漏磁与发热问题、提升调相机端部冷却系统综合效能提供理论支撑，为助力特高压输电系统大型同步调相机发展提供理论保障。