大规模风电直流混联电网故障连锁反应机理与主动保护研究

Wind power is collected near the DC converter station and coupled with the DC converter station via electromagnetic constraint and control algorithm. This AC/DC hybrid power grid is gradually formed. Grid fault easily induces wind turbine and DC converter station failure, exit and status mutation, making a single fault of the grid causing multipoint continuous reaction. Under the influence of the non-linear variation of powers contributed by the wind turbine and DC converter station, the cascading failures changes from the successive tripping caused by the active power flow shift to the successive reaction of the equipment caused by high active and reactive power impacts, resulting in the cascading failure process unclear, lack of protection and other problems.. This research focuses on employing the fast power control ability of wind turbine and DC converter station in power system protection. By studying the form, characteristics and mechanism of chain reaction of wind turbine and DC converter station under grid fault, the safety domain and its modeling theory of fault cascading reaction are studied. The active protection method for fault cascading reaction that takes full advantage of the power control ability and impact resistance ability of wind turbine and DC converter station and coordinates with the three lines of defense are studied. The key problems contained the multi-time scale coupling analysis, the safety characterization of grid fault and the coordination of protection and control of source and grid are solved. This study will provide the necessary theoretical reference and technical measures for the safe operation of power system.

风电在直流落点近区大规模汇集并经电磁约束和控制算法与直流换流站耦合的交直流混联电网格局逐渐形成。电网故障易诱发风电机组、直流换流站失效、退出和状态突变，导致电网局部单一故障易演变为全局多点连锁反应。风电机组、直流换流站功率具有受控性和非线性特点，使得电网连锁故障由有功潮流转移引起的相继跳闸向大有功和大无功冲击引发的多种设备相继反应转变，导致电网连锁故障过程不清、保护能力不足等问题。. 本项目着眼于风电机组、直流换流站快速功率控制在电网故障保护中的应用，通过研究电网故障下风电机组、直流换流站连锁反应的形式、特征和机理，研究电网故障连锁反应安全域及其建模理论，研究充分利用风电机组、直流换流站功率控制能力和耐冲击能力并与三道防线协调的故障连锁反应主动保护方法，在设备多时间尺度耦合分析、电网故障安全性刻画和网源保护与控制协调等核心问题上形成突破，为电力系统故障安全运行提供必要的理论参考和技术措施

随着风电装机容量的持续增加以及强直弱交电网的逐步形成，电网连锁故障的风险不断显现。风电机组和直流输电的运行控制原理与传统同步机、交流输电相比具有本质区别，使得风电直流混联电网呈现强耦合、脆弱性、高可控性等新的网源特性。针对风电机组、直流换流站故障响应引起电网故障形态的新变化，本项目立足于风电机组、直流换流站及交流电网故障保护和控制的协调，着眼于风电机组、直流换流站快速功率控制能力在电网故障保护中的应用。.本项目通过风电直流混联电网故障过程的等值建模，从故障响应特性的时间演变与故障影响的空间传播2个方面，研究了电网故障连锁反应的形式、特征和机理，为连锁故障的保护提供依据；考虑外部环境影响因素与电网电气参数动态交互作用，考虑风电及直流设备安全边界、直流换相失败边界和运行约束，刻画了设备、系统耐冲击能力和快速功率控制能力，进而提出了表征电网故障连锁反应安全性的安全域理论及其建模方法；通过充分利用风电变流器、直流换流器耐冲击能力、充分挖掘风电机组、直流换流站及交流电网功率控制能力，提出了抑制和阻断故障连锁反应的主动保护方法，为现代电力系统故障安全运行提供必要的理论支撑和技术措施。