It is essential to alleviate the thermoelectric contradiction and further improve the unit flexibility. Taking the heating retrofit of a domestic power generation company as the example

the application of the zero output technology of low-pressure cylinder of 300 MW unit turbine is discussed. This study presents a security analysis on the last stage blades of the low-pressure cylinder under the operating condition of zero output of the low-pressure cylinder. The technical measures are established including improving the operation monitoring and measuring points in low-pressure cylinder

the metal spraying of the last stage blades

the arrangement of the cooling steam system for low pressure through-flow and the maintaining of high vacuum of the low-pressure cylinder. The heat supply and peaking capacity after the heating retrofit are analyzed and the economic benefit after the heating retrofit is also calculated. The results show that

under the premise of ensuring the safe operation of the unit

the zero output technology not only realizes the thermoelectric decoupling

but also further reduces the loss of cold source of the turbine and improves the operating economy of the units.