Is Shuikou Hydropower Station a state-owned enterprise or a central enterprise?

First of all, there is something wrong with your question itself. State-owned enterprises and central enterprises are not juxtaposed concepts. State-owned enterprises are state-owned enterprises. In Chinese mainland, state-owned enterprises can be subdivided into state-owned enterprises owned by the central government and state-owned enterprises owned by local governments, among which state-owned enterprises owned by the central government are referred to as central enterprises for short. Therefore, central enterprises are small concepts, state-owned enterprises are big concepts, and central enterprises are a kind of state-owned enterprises.

Back to your question. The ultimate control right of Shuikou Hydropower Station in Fujian belongs to the State Grid, which is a central enterprise, so Shuikou Hydropower Station should also be a central enterprise and a state-owned enterprise.