[Objective] To address the problem of insufficient main steam and reheat steam temperatures under lowload operating conditions in double-reheat units

this study aims to improve the wide-load high-efficiency operation capability of such units and achieve collaborative optimization between steam temperature enhancement and operational flexibility. [Methods] A steam-electric dual-drive induced draft fan scheme is proposed

in which a portion of superheated steam is extracted to drive the induced draft fans. Simulation studies are conducted on a constructed thermodynamic system model of a 1 000 MW ultra-supercritical double-reheat generating unit. The steam temperature improvement effects under different extraction steam flow rates are analyzed

and the impacts on economic performance indicators including turbine heat rate and power generation coal consumption rate are evaluated. Exergy analysis is employed to reveal the distribution of exergy losses among major components and the variation patterns of exergy efficiency. [Results] At 30%THA load

extracting steam from the secondary superheater outlet to drive the induced draft fans can increase the main steam temperature by 16.8 ℃ and the first and second reheat steam temperature by 19.1 ℃ and 20.7 ℃

respectively

while simultaneously reducing the turbine heat rate and power generation coal consumption rate. The boiler is identified as the component with the largest exergy loss in the unit

and the proposed scheme can improve the overall exergy efficiency of the unit by approximately 4.3 percentage points. [Conclusion] The steam-electric dual-drive induced draft fan scheme provides a feasible technical pathway for addressing the problems of steam temperature deficiency and insufficient operational flexibility in ultra-supercritical double-reheat generating units under low-load conditions.