一次调频参数对超超临界二次再热机组性能的影响

Primary frequency regulation characteristics of double reheat unit have significant impacts on the operation stability and flexibility of power system due to its complicated flow process and large inertia. Based on the GSE simulation platform, the dynamic simulation models of the ultra-supercritical double reheat generation unit and primary frequency regulation were developed and validated by virtue of the combination of JTopmeret module and self-defined program. Then, the response characteristics of the thermal parameters in the double reheat unit during the primary frequency regulation process were studied. The effects of the load step amplitude and the speed droop on the primary frequency regulation characteristics were analyzed. It is discovered from the results that in the primary frequency regulation process of the double reheat unit, with step increase of the load power the real-time frequency will drop rapidly and DEH turbine control system will immediately take measures during dynamic processes, the real time frequency is less 50 Hz. Once the system reaches steady state, the relative change of flow volume and pressure of the primary and secondary reheat steam will be greater than those of the main steam. During the primary frequency regulation of the double reheat units, the increase of load step amplitude or the reduction of the speed droop, will both boost the dynamic overshoot of the frequency, and prolong the time duration for frequency regulation. Compared with single reheat generation units, the primary frequency control systems of double reheat units demonstrate faster response, whereas their maximum overshoot is larger during the regulation process. This work is supported by National Key Research and Development Program of China (No.2017YFB0602101).