Abstract: In order to meet the urban heating demand and respond to the power grid dispatching demand, all cogeneration units are accelerating the implementation of corresponding heating technology transformation projects. In the transformation process, due to the large power load of new process equipment, the problem of insufficient auxiliary power margin is often encountered. In this paper, through practical cases, the design load is checked according to the auxiliary power design regulations, the actual operating conditions of process equipment are analyzed, and the load rate method is used to recheck. Theoretical analysis and actual operation data show that the heating technical transformation projects have little impact on the auxiliary power load, and most technical transformation projects do not need to increase the capacity of high-speed auxiliary transformer or add high-speed auxiliary transformer.