Abstract: When unified large-capacity renewable power generation and adjacent thermal power generation are suffered from fault disturbance, both rotor swing of synchronous generators and fast output variation of renewable power will cause terminal voltage fluctuation, resulting in frequent low-voltage ride-through (LVRT) control actions within renewable power generation units. One reasonable way to solve this problem is to dispatch reactive power output of renewable power plant to maintain its terminal voltage above LVRT threshold. In this paper, the relationship between terminal voltage and reactive power output of renewable power plant was established according to the unified transmission system operation conditions. This V-Q relationship could be used to determine reactive power demand of the renewable power generation plant. Based on the analyses above, a comprehensive reactive control strategy was proposed after considering both reactive power capability of installed STATCOM and renewable generation units within the renewable power plant. Cases studies verify the effectiveness of the proposed method, and can be referred for practical engineering applications.