Abstract: Abstract:Through the establishment of the heattoelectric ratio calculation model in heating unit and variable condition calculation, this paper studies and analyzes the factors affecting the heattoelectric ratio in heating unit. The research results show that the heattoelectric ratio relates with the heat input ratio of condensing steam cycle and heating cycle, the thermoelectric conversion efficiency of condensing steam cycle and heating cycle and other factors. Among them, the heat input ratio of condensing steam cycle and heating cycle has the most impact. The ratio increases, the heattoelectric ratio decrease. The variable condition calculation of a 300MW heating unit shows that the heattoelectric ratio increases with the heating extraction quantity, and descends by the increase of the unit electric load, increases with the heating extraction steam pressure, increases with the main steam temperature and pressure, basically remain unchanged when the exhaust steam pressure changes.

Key words: Key words:the heattoelectric ratio, heating unit, variable condition, mathematical model, influencing factors, theoretical analyze