Electric Power ›› 2021, Vol. 54 ›› Issue (6): 111-118,152.DOI: 10.11930/j.issn.1004-9649.202101111

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Refined Modeling for Power Response Characteristic of Thermal Power Unit under Primary Frequency Control

SHENG Kai1, ZOU Xin2, QIU Jing4, ZHU Xiaoxing3   

  1. 1. State Grid Hunan Electric Power Company Research Institute, Changsha 410007, China;
    2. State Grid Hunan Electric Power Co., Ltd., Changsha 410004, China;
    3. Hunan Provincial Key Laboratory of High Efficiency & Clean Thermal Power Technology, Changsha 410007, China;
    4. Hunan Xiangdian Test & Research Institute Co., Ltd., Changsha 410006, China
  • Received:2021-01-22 Revised:2021-03-22 Published:2021-06-05
  • Supported by:
    This work is supported by Hunan Science and Technology Innovation Platform and Talent Program (No.2016TP1027) and the Science and Technology Project of State Grid Hunan Electric Power Co., Ltd. (No.5216A520000D)

Abstract: Due to the strong-nonlinearity characteristics of the power response of thermal power units, it is difficult to represent the practical power characteristics precisely in terms of the typical linear model. In this paper, through the analysis of the impacts of key factors such as the discharge characteristics of steam turbine valves and throttle pressure on the power response characteristics under primary frequency control, the steam turbine’s valve discharge characteristic and throttle pressure coupling function are introduced as well as the throttle pressure model and the dynamic conversion factor between first stage pressure and load. Then the refined model of power response under primary frequency control is established based on the typical steam turbine model. Finally, the performance of the established model is validated in combination with the primary frequency control test on an actual 660 MW supercritical unit. The results indicate that compared with the typical model, the proposed model demonstrates higher accuracy regarding the power characteristics under primary frequency control.

Key words: thermal power unit, power response, valve discharge characteristic, throttle pressure, dynamic conversion factor, accurate model, primary frequency control