直流调制对大型交直流互联电网安控的影响

Impact of DC Modulation on Safety and Stability Strategy in AC/DC Hybrid System

随着大电网互联工程的推进,交直流混联运行成为趋势。大型直流系统接入系统后大大改变了原有电网运行特性,直流故障可能对电网运行带来极大隐患。为此,以四川电网为例,针对直流闭锁故障分析了不同安控措施条件下大电网的稳定恢复特性。综合比对分析认为:在发生系统闭锁故障后快速提升直流功率,可避免在系统中进行切机切负荷,或者降低切机切负荷量。但直流短时过负荷后的大量功率释放可能对系统造成更为严重的冲击,导致系统稳定水平下降。

With the advancements of interconnected power system, AC/DC hybrid operation become the trend. The intereonnection with large DC system can significantly change the operation characteristics of original grid, and DC fault may generate great potential peril to grid. In this paper, the transient characteristics of Sichuan power grid with different safety control measures after DC block fault are analyzed. Research results indicate that augmenting the power of the healthy pole after HVDC blocking can avoid generator tripping and load shedding, or decrease the amount of generator tripping and load shedding. But the DC power releasing after short-time over loading might perturb the system seriously, thus damage the stability of power system.