【作者】 刘涛；

【导师】 李博通； 李盛伟；

【作者基本信息】 天津大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 故障自清除型直流配电网可以利用换流器的故障电流自清除能力并结合隔离开关实现故障元件的快速隔离,解决了直流配电网的故障电流清除难题,是当前国内外研究热点及未来配电网的重要发展方向。目前直流配电网的故障自愈技术大多针对的是基于直流断路器的直流配电网,而故障自清除型直流配电网与其在故障特性、故障元件识别及故障隔离后恢复等方面有明显区别,因此针对故障自清除型直流配电网的故障自愈技术研究有重要的理论和实用意义。针对基于故障自清除型换流器的直流配电网的故障自愈技术,本文进行了深入研究,主要研究内容及成果如下:研究了故障自清除型直流配电网极间故障下的故障特性。在分析不同位置发生极间故障时的等效电路方程的基础上,提出了一种能表征系统内母线与故障位置关联关系、且仅需使用母线电气量的母线虚拟电压计算方法,总结了故障自清除型直流配电网故障后的母线虚拟电压特性。研究了适用于故障自清除型直流配电网的故障元件识别方案。在分析不同位置故障时母线虚拟电压大小的基础上,提出了一种基于母线虚拟电压比值的故障元件主识别方法。考虑到主识别方法的识别死区问题,分析了换流器部分全桥子模块投入过程中的放电特性,提出了一种利用子模块投切与隔离开关配合的基于电荷转移量的故障元件辅助识别方法。针对不同位置的瞬时性与永久性故障,结合主、辅识别方法,形成了完整的故障元件识别及隔离方案。研究了适用于故障自清除型直流配电网的故障恢复方法。通过分析恢复过程中系统安全、经济运行的约束条件,提出了适用于伪双极系统的最优恢复运行点计算方法及计算流程。针对不同控制方式、不同类型的换流器,研究了不同恢复策略对恢复效果的影响,针对不同位置故障,给出了对应的整个系统的恢复逻辑。更多还原

【Abstract】 The fault self-clearing DC distribution network can realize the rapid isolation of fault components by using the fault current self-clearing ability of the converter combined with the isolation switch,which solves the problem of fault current clearing in the development of DC distribution network.It is a research hotspot at home and abroad and an important development direction of the distribution network in the future.At present,the fault self-healing technology of DC distribution network is mostly aimed at the DC distribution network based on DC circuit breaker,and the fault self-clearing DC distribution network is obviously different from it in fault characteristics,fault component identification and recovery after fault isolation.Therefore,the research on the fault self-healing technology of fault self-cleaning DC distribution network has important theoretical and practical significance.The fault self-healing technology of DC distribution network based on fault selfclearing converter is deeply studied in this thesis.The main research contents and results are as follows:The fault characteristics of self-clearing DC distribution network under inter-pole faults are studied.Based on the analysis of the equivalent circuit equation when the faults occur at different locations,a calculation method of bus virtual voltage is proposed,which can represent the relation between bus and fault location in the system,and only the electricity quantity of bus is used,and the characteristics of bus virtual voltage after fault self-clearing DC distribution network are summarized.A fault element identification scheme for fault self-clearing DC distribution network is studied.Based on the analysis of the virtual voltage of bus at different fault locations,a method of main recognition of fault components based on the virtual voltage ratio of bus is proposed.Considering the dead zone problem of the main identification method,the discharge characteristics of partial full bridge submodules in the converter are analyzed,and an auxiliary identification method of fault components based on charge transfer is proposed by using submodule switching and isolating switch.According to the instantaneous and permanent faults in different locations,a complete scheme of fault component identification and isolation is formed by combining the main and auxiliary identification methods.A fault recovery method for DC distribution network with self-clearing fault is studied.By analyzing the constraints of safe and economical operation of the system in the recovery process,the calculation method and flow of the optimal recovery operation point suitable for pseudo bipolar system are proposed.In view of different control modes and different types of converters,the influence of different recovery strategies on the recovery effect is studied,and the corresponding recovery logic of the whole system is given for different faults.更多还原