Optimal capacity configuration of hydro-wind-PV hybrid system and its coordinative operation rules considering the UHV transmission and reservoir operation requirements

Hydropower is utilized to regulate the fluctuations of wind and photovoltaic (PV) power in the hydro-wind-PV renewable energy system (H-RES), which can effectively improve energy utilization. However, it is challenging to determine the optimal capacity configuration considering power delivery and power output characteristics simultaneously. This study launched a research framework for determining the optimal capacity configuration and short-term coordinative operation rules considering the ultra-high voltage (UHV) transmission and reservoir operation requirements. Firstly, a scenario analysis technique was proposed to generate joint wind-PV scenarios considering the uncertainties and correlation. Secondly, a two-stage adaptive complementary operation strategy was presented. Subsequently, a nested mathematical model of capacity configuration and coordinated operation optimization of H-RES was established. Finally, the framework was applied to a case study in Qinghai Province, China. The results show that: (1) it is recommended the H-RES wind-PV penetration rate should not exceed 50% when the system is configured; (2) the proposed model and strategy can eliminate hydropower abrupt fluctuations by 32.7% on average; (3) the power grid role of the H-RES varies by season and it shows great potential of bearing the baseload in summer and autumn. Therefore, this research is instructive in the planning and actual operation of the large-scale H-RES.