直流输电工程模块化最后断路器保护策略分析

文中综述了目前直流工程最后断路器保护研究及应用现状,针对目前各种最后断路器保护策略在实际工程应用中存在的缺点,提出了一种模块化的最后断路器保护策略。模块化指按阀组配置最后断路器保护功能模块,功能模块由输入信号、输出信号、逻辑判据组成。保护策略为:在最后断路器保护使能的情况下,与运行阀组存在电气连接的交流母线上无交流出线相连且满足功能辅助判据则最后断路器保护动作,立即闭锁该运行阀组。理论分析和工程实际案例表明,该保护策略适用于不同的直流运行方式和交流场接线方式,模块化配置灵活便于校验和重用,无需新增硬件设备节省投资,无额外延时动作迅速,模拟量辅助判据避免保护误动,更好地保障了设备和电网安全。

Analysis of modular last line protection strategy of HVDC project

The current research and application status of last line protection in HVDC project are summarized. To overcome its disadvantages in existing engineering application, a modular LLP strategy is proposed. The module is equipped in the controller of each valve group, and it consists of input signals, output signals and corresponding LLP logic. When LLP is activated, if there is no power line connected to the valve group in service through the busbar and moreover certain auxiliary criterion is met, LLP would act and block the corresponding valve group immediately. Theoretical analysis and practical applications prove that the modular LLP can adapt to different kinds of HVDC and AC yard topology. The modular LLP is easier to configure , reuse and test. Without additional investment in hardware, the modular LLP can also achieve good performance in operating speed and reliability, and it will contribute to the safety and stability of the grid.