基于BPA的大电网紧急直流功率支援策略研究

针对特高压交直流混联大电网的结构特点，研究了紧急直流功率支援策略对实际电网安全稳定运行的影响。基于PSD-BPA仿真平台，分析了直流功率提升策略对系统稳定性的作用，得到合适的功率支援开始时刻、支援量和持续时间，通过在系统回摆过程中采取功率回降策略改善紧急功率支援的效果。针对直流有功功率大方式调制，提出了直流调制附加控制器输入信号的选取原则，并与功率提升/回降方式比较，对比分析了两种方式下紧急功率支援的有效性。仿真结果表明，相比于功率提升/回降方式，有功功率调制改善了后续摆的稳定裕度及阻尼，紧急功率支援效果较为理想，为实际电网附加稳定控制策略的制定提供参考。

Research of emergency DC power support strategies for large-scale power grid based on PSD-BPA

In allusion to the structural characteristics of UHAC/UHDC hybrid, the influence of emergency DC power support (EDCPS) on secure and stable operation of actual grid is studied. The effects of power upgrade strategy on system stability are analyzed based on PSD-BPA to obtain the proper starting-time, the proper amount and the proper duration of power support. The power backdown strategy is adopted during swing-back process to improve the results of emergency power support. Contraposing the active power modulation strategy, the selection principle of input signals for DC auxiliary controller is put forward. The effectiveness of active power modulation and power upgrade (or backdown) as emergency power support strategies is analyzed by comparison. Simulation results indicate that active power modulation improves the stability margin and damping of following-swing and has better results of emergency power support. Study results are available for reference in the drafting of additional stability function for actual AC/DC hybrid power grid.