Installed capacity comparison and selection for hybrid and conventional pumped storage power stations

Pumped storage power stations (PSPSs) play a vital role in enhancing power system stability. Common types of PSPSs include hybrid and conventional ones. However, the installed capacity substitution ratio between the two types remains unclear under equivalent improvements in power system efficiency. This study considers both hybrid and conventional PSPSs and develops scheduling models for hydro-thermal-wind-solar-storage multi-energy complementary systems to evaluate indicators, including the total stored energy in cascade hydropower stations and power generation guarantee rate. Using the Geheyan-Gaobazhou cascade hydropower stations as a case study, the results show that, compared with conventional PSPSs, incorporating hybrid PSPSs increased the total stored energy in cascade hydropower stations at the end of the scheduling period by 47.91% and improved power generation reliability by 2.87%. Furthermore, when the system power shortage amounts to 10 million kWh, a hybrid PSPS requires only 0.76 times the installed capacity of a conventional PSPS to achieve higher power generation guarantee rate while enhancing the total stored energy in cascade hydropower stations. This study provides a scientific reference for the installed capacity selection of PSPSs.