Seismic Performance Assessment and Enhancement Strategy for UHV Converter Stations

Ultra-high voltage (UHV) converter stations play a crucial role in long-distance, high-capacity power transmission. The seismic performance of substations is directly related to the stability of power systems. Based on the equipment composition and functional connectivity of a typical converter station, an equivalent capacity network model of the converter station system is established. The post-earthquake residual transmission capacity of the converter station system is transformed into a maximum flow problem, which is solved using the Dinic algorithm to achieve efficient evaluation of seismic performance. The assessment results indicate that the probability distribution of the converter station’s power operation states is significantly affected by the peak ground acceleration (PGA). The probability of low-power operation state rises with the increase of PGA, while the probability of high-power operation state decreases. Furthermore, a sensitivity analysis identifies the DC filter group (DCFG), gasinsulated transmission line (GIL), and wall bushing (WB) are the critical subsystems of the specified converter station. Reinforcing key subsystems can improve the seismic performance, but its effect is significantly changed by the variation of PGA. Results show the effect of strengthening key subsystems is limited when seismic action significantly exceeds the initial seismic fortification goal.