Short-term scheduling strategy of hydro-photovoltaic complementary system under high water level and limited storage conditions of cascade reservoirs in Kashgar

The large-scale grid integration of photovoltaic (PV) power in Kashgar has brought significant challenges due to its intermittency and volatility. To address this, hydro-PV complementary systems, leveraging the fast regulation and flexible operation of hydropower stations, offer an effective solution. However, hydro-PV complementary dispatching remains underdeveloped in Kashgar, particularly at the end of the flood season, when reservoirs operate at high water levels and inflow is abundant. The integration of PV generation places dual pressure on reservoirs to store water and absorb fluctuating solar energy, often resulting in abandonment of both water and PV power in the absence of effective scheduling. Thus, this paper constructs the hydro-PV complementary scheduling model in Kashgar and extracts the short-term scheduling strategy under high water level operation and limited storage capacity. The main findings are as follows:(1) Compared to traditional cascade reservoir optimization, increases daily power generation by 1.68 %, 1.38 %, and 7.58 % on three typical days while achieving full renewable energy absorption; (2) Within the cascade system, the ARTS reservoir plays a dominant role in short-term regulation, contributing 75 % and 62 % to PV fluctuation smoothing under strong and normal PV output scenarios, respectively; (3) On a seven-day dispatching scale, ensuring full PV integration without water abandonment requires reserving 0.4 m and 2.84 m of dispatchable water level margins at the XBD and ARTS reservoirs, respectively. This study fills a critical research gap regarding hydro-PV complementary scheduling in Kashgar and provides practical decision-making guidance for future multi-energy coordinated operation under high water level and limited regulation capacity conditions.