Abstract: High and low pressure bypass combined heating supply and low-pressure cylinder zero output technology are two important flexibility transformation technologies, which can effectively improve thermal power units’ peak regulation capacity and heating capacity. In this paper, for the two same model 350 MW supercritical units of North China power grid, a therma lsystem simulating software named Ebsilon is used to build the high and low pressure bypass combined heating supply and low-pressure cylinder zero output model, whose reliability are demonstrated by actual field performance tests. The models’ full operation interval calculation results show that：the high and low pressure bypass combined heating supply model has better thermoelectric decoupling capacity because of it's maximum heating load capacity is 57.27 MW more and minimum electrical load capacity is 141.04 MW less than the low-pressure cylinder zero output model; The low-pressure cylinder zero-output model has a higher energy utilization rate because of its’ electrical load is 61.012 MW higher than high and low pressure bypass combined heating supply model when they have the same main steam and heating steam. Under the existing peak regulation revenue mechanism of North China Power Grid, the low-pressure cylinder zero-output heating can obtain a higher maximum comprehensive income when the main steam flow is less than 505 t/h; the two technologies can obtain the same max comprehensive benefit when the main steam flow is 505 t/h; the high and low pressure bypass combined heating supply model can obtain higher maximum comprehensive revenue when the main steam flow rate is greater than 505 t/h.

Key words: thermoelectric decoupling, high and low pressure bypass combined heating supply, zero output of low-pressure cylinders, thermoelectric properties, peak shaving benefit