By taking an integrated solar combined cycle system(ISCC) consisting of trough solar field and conventional combined cycle power plant as the research object

the thermodynamic time-by-time characteristics of the solar field and the ISCC system in four typical days are analyzed

combining the first law and the second law of thermodynamics. The results show that

with the increase of solar radiation intensity

the solar power generation increases

while the power generation of CCPP decreases gradually

forming a complementary trend. In addition

with the increase of solar radiation intensity

the working fluid mass flow rate of solar field

the solar field efficiency

the solar-to-electric efficiency and the fossil fuel based thermal efficiency of the ISCC system increase

while the exergy destruction rate decreases. The results indicate that the performances of the ISCC system can be improved significantly by enabling the solar field. Moreover

according to analysis of the main evaluation indexes

the annual solar power generation is 27.25 MW·h

the annual fuel saving can reach up to 3 664.6 t

the annual CO2 emission reduction is 10 077.66 t

and the annual fuel saving cost is 12.106 4 million yuan. The research can provide theoretical basis for design and retrofitting for ISCC systems.