## 4 Results and Analysis  
This paper takes a hydropower station in the upper reaches of the Yellow River in China and a photovoltaic station in Gansu Province as examples for example analysis. Among them, the hydropower station is located in the upper reaches of the basin and is a comprehensive reservoir with annual regulation capacity. The total reservoir capacity of the reservoir is 521 million cubic meters, the control basin area is 26,000 square kilometers, and the average annual flow rate is 275 cubic meters per second. The total installed capacity of the hydropower station is 300 MW and the maximum reference power generation flow is 1000 cubic meters per second. The reservoir is mainly power generation, with comprehensive utilization benefits such as flood control and industrial irrigation. The total installed capacity of photovoltaic is 100 MW. The photovoltaic field involved in the terrain is high, the annual air volume is sufficient, with a plateau continental climate. The first phase of the power station was connected to the grid in November 2013 with a capacity of 50 MW, the second phase was connected to the grid in June 2014 with a capacity of 50 MW, and the total installed capacity of the two phases was 100 MW. Table 2 shows the main technical indexes of reservoir hydropower station. According to the actual operation of the reservoir for many years, the water level-storage capacity relationship of the reservoir is shown in Figure 11. \begin{table}
\begin{tabular}{c c c c c} \hline \hline Catchment area (\(10^{4}\) km\({}^{2}\)) & Aggregate storage capacity (\(10^{8}\) m\({}^{3}\)) & Regulating storage (\(10^{8}\) m\({}^{3}\)) & Read storage (\(10^{8}\) m\({}^{3}\)) & Flood storage (\(10^{8}\) m\({}^{3}\)) \\ \hline
2.6 & 5.21 & 2.21 & 2.29 & 1.91 \\ \hline \begin{tabular}{c} Firm output \\ (MW) \\ \end{tabular} & \begin{tabular}{c} Maximum reference \\ traffic (m\({}^{3}\)/s) \\ \end{tabular} & \begin{tabular}{c} Installed capacity \\ (MW) \\ \end{tabular} & \
\begin{tabular}{c} Mean annual energy \\ production (\(10^{8}\) kWh) \\ \end{tabular} &
\begin{tabular}{c} Annual runoff \\ (\(10^{8}\) m\({}^{3}\)) \\ \end{tabular} \\ \hline
7.8 & 1000 & 300 & 14.63 & 86.72 \\ \hline \begin{tabular}{c} Check flood level \\ (m) \\ \end{tabular} & \begin{tabular}{c} Design flood level \\ (m) \\ \end{tabular} & \begin{tabular}{c} Normal water level (m) \\ \end{tabular} & \
\begin{tabular}{c} Flood limited water \\ level (m) \\ \end{tabular} &
\begin{tabular}{c} Dead water level \\ (m) \\ \end{tabular} \\ \hline
708.8 & 703.3 & 704 & 695 & 685 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The parameter table of the hydropower station. Figure 11: Characteristic curve of the hydropower station: (**a**) reservoir water level—storage capacity and (**b**) downstream water level—discharge flow. The example is mainly aimed at the joint dispatching process of regulation and storage and photovoltaic power generation in the water withdrawal stage of reservoir flood season, and the dispatching process in other periods (such as flood dispatching or profit dispatching) is executed according to the designed dispatching rules. It can be seen from the previous analysis that there is a contradictory relationship between the flood control risk value and the water storage benefit difference. When the pre-storage capacity increases, the water storage benefit difference will decrease and the flood control risk value will increase. At the same time, with the decrease in the pre-storage water, the power generation flow of the hydropower station increases. In order to ensure that the water is not abandoned or to reduce the water abandoned by the hydropower station in the flood season, and maximize the utilization of flood resources, the regulation ability of the hydropower station will also be affected, which will affect the volatility of the hydropower and photovoltaic joint dispatch. When the forecast uncertainty level increases or the acceptable risk decreases, the upper limit of the flood control level will decrease.