青藏直流接入西藏电网数模混合仿真

Digital/Analog Hybrid Simulation of Tibet Grid Integrated With ±400 kV DC Transmission Line From Qinghai to Tibet

青藏直流接入西藏电网后,西藏电网呈现"大直流小电网"的特点。利用全数字实时仿真装置Hypersim模拟青海电网、西藏电网以及青藏直流的一次系统,采用与实际工程特性一致的Mach2控制保护装置实现直流的控制保护功能,对交直流系统的相互影响进行仿真研究,包括青藏直流的特殊降压起停方式,直流线路故障再起动逻辑,以及交流系统故障对青藏直流的影响。仿真结果充分验证了青藏直流采用特殊的降压起停方式和修改后的直流线路故障再起动逻辑的可行性,为青藏直流工程的顺利投产和安全运行提供了技术支撑。

After the integration of Tibet power grid with ？400kV DC transmission line from Qinghai to Tibet,the peculiarity of high capacity of DC system and low capacity of AC power grid appears.The interaction between the DC system and the AC system,including the special reduced voltage start and stop modes of the DC system,the post-fault restart logic for DC transmission line and the influences of faults occurred in AC grid on DC system,is researched by simulation.The primary systems of Qinghai power grid,Tibet power grid and DC system connecting Qinghai power grid with Tibet power grid are simulated by full-digital real-time simulator Hypersim;the Mach2 system,whose control characteristics are consistent with those of the devices adopted in engineering practice,is utilized to simulate control and protection functions of DC system.The feasibility of the special reduced voltage start and stop modes for the DC system and that of the modified post-fault restart logic for DC transmission line are fully validated by simulation results,thus the two measures can provide technological support for smoothly putting the ？400kV DC transmission project from Qinghai to Tibet into service and secure operation of this DC transmission project.