特高压直流输电线路故障控制特性与暂态保护研究

The travelling wave protection which used widely in HVDC transmission line protection is easy to be disturbed by lightning strike,and sensitivity is not enough when high resistance fault happens,so it is necessary to study the new transient based protection.The fault controlling characteristic of UHVDC transmission line and transient based protection will be studied in this research problem.The main study content and key science problem of the research is: ①Study the fault characteristic of UHVDC transmission line ,study the interaction relationship of fault and controlling system, point out the influence of different controlling mode and controlling parameter on the UHVDC transmission line fault characteristic;②Analyse the frequency characteristic of UHVDC line and line boundary,study the influence of fault position on fault transient signal frequency characteristic which detected by protector;③Invent the single-ended and double-ended transient based protection methods of UHVDC transmission line which use protector to distinguish the internal fault and external fault of the opposite side;④Study the internal and external fault criterion,fault distance criterion,fault pole criterion,high resistance fault detecting criterion , lightning strike disturbance criterion,and so on.The study target is:point out the interaction relationship of fault and controlling system,establish the transient based protection method of UHVDC transmission line which use protector to distinguish the internal and external fault of the opposite side,establish the action criterion.

目前广泛应用于直流输电线路的行波保护易受雷电等暂态现象的干扰，在线路高阻接地时存在灵敏度不够的缺点，有必要研究新型的直流输电线路暂态保护。项目围绕特高压直流输电线路故障控制特性和暂态保护展开研究。主要研究内容和关键科学技术问题是：①研究特高压直流线路的故障机理以及故障与控制系统的相互作用关系，揭示不同控制方式和控制参数对特高压直流线路故障暂态特征的影响作用；②分析直流线路和边界的频率特性，研究故障位置对保护安装点检测到的故障暂态信号高频量频率特性的影响；③综合考虑线路与边界对高频量的衰减作用,提出利用保护元件区分对侧区内外故障的特高压直流线路单端暂态保护原理和双端暂态保护原理；④研究特高压直流线路区内外故障辨识、故障距离、故障选极、高阻接地检测、雷电干扰剔除等判据。研究目标是揭示线路故障与控制系统的相互作用关系，建立利用保护元件区分对侧区内外故障的特高压直流输电线路暂态保护原理和动作判据。

依据云广特高压直流输电系统实际参数，建立云广特高压直流输电系统仿真模型；对特高压直流输电线路频率特性、特高压直流输电线路边界频率特性及故障位置对保护安装点故障暂态信号频率特性的影响进行研究,得出线路长度达到一定长度时，线路对高频率的衰减将超过边界对高频量的衰减作用的结论；研究直流输电线路非故障性雷击、接地短路和故障性雷击的暂态特征，提出雷电干扰的识别方法；研究特高压直流输电换相失败机理、影响特高压直流输电换相失败的因素、特高压直流输电换相失败判断标准、特高压直流输电换相失败避免措施，提出了换相失败故障诊断的方法；研究特高压直流输电线路电压暂态保护，提出利用保护元件区分对侧区内外故障的特高压直流输电线路单端、双端电压暂态保护原理，分别提出了其保护动作判据；提出基于希尔伯特黄变换的特高压直流输电线路单端电流方向暂态保护、基于形态学的特高压直流输电线路单端电流方向暂态保护两种保护实现方法；研究基于高频量衰减特性的特高压直流输电线路故障测距原理。提出基于高频量衰减特性的特高压直流输电线路神经网络双端故障测距、基于模量传输时间差的特高压直流输电线路神经网络单端测距、利用模量首波头模极大值比的特高压直流输电线路神经网络单端测距三种测距方法。