陕北-武汉特高压直流输电工程无功控制策略研究

针对陕武工程分层接入系统的复杂性和特殊性,对其无功控制策略进行了优化和完善。在原有无功控制策略的基础上增加了过压快切、紧急停机后的快切以及后备无功控制等功能。过压快切旨在当交流侧电压由于故障急剧升高时,能够在短时内快速切除交流滤波器,保证交流母线电压运行在安全水平。紧急停机后的快切是指在陕武工程出现紧急停运后,无功控制功能迅速切除在投滤波器组,确保交流网电压稳定。后备无功是指当执行无功控制功能的两套直流站控主机全部不可用之后,实现后备无功控制功能的极控接口屏PCI能够根据交流母线电压变化,实现交流滤波器的切除,从而保证交流母线电压稳定,维持直流系统稳定运行。通过仿真试验验证了新增策略的正确性,最后对后备无功控制提出了改进建议。

Reactive power control strategy for the Shanbei-Wuhan UHVDC transmission project

Given the complexity and particularity of the hierarchical connection system of the Shanwu Project, its reactive power control strategy has been optimized and perfected. On the basis of the original reactive power control, overvoltage fast switching, fast switching after emergency shutdown, and backup reactive power control function are added. The overvoltage fast cut is designed such that when the AC side voltage rises sharply because of a fault, the AC filter can be quickly removed to ensure that the AC bus voltage runs at a safe level. Quick resection means that after an emergency shutdown of the project, the reactive power control function quickly switches off the filter banks to ensure the stability of the AC grid voltage. Back-up reactive power control means that when the two sets of DC station control systems are unavailable, the polar control interface panel PCI can effect the removal of the AC filter according to the AC bus overvoltage, thereby ensuring that the AC bus voltage is stable and maintaining the stable operation of the DC system. A simulation experiment verifies the correctness of the new strategy. Finally, the paper offers suggestions for improvement of backup reactive power control. This work is supported by the Science and Technology Project of State Grid Corporation of China (No. SGTYHT/ 18-JS-206).