Integrated unit commitment and economic dispatch of combined heat and power system considering heat-power decoupling retrofit of CHP unit

Low-carbon development of a power system is realised via the flexibility retrofit of thermal power units with heat-power decoupling (HPD) of combined heat and power (CHP) units providing the necessary transformation pathway. First, this study examined the primary measures of HPD of CHP units and their impact on unit flexi-bility. Thereafter, aiming to realise flexibility retrofit of thermal power units, a detailed HPD model on the power side was proposed. In addition, the heat delay and heat loss in the process of heat transmission were also considered, followed by the establishment of a simulation method for unit commitment and economic dispatch (UCED) of CHP system considering HPD. Subsequently, based on IEEE RTS-79 test system, the effectiveness of the model and method proposed in this study was proven. Moreover, the proposed UCED method was applied to systematically analyse the comprehensive benefits achieved via the use of the HPD retrofit of the CHP units. The results showed that HPD retrofit has significant benefits in reducing dispatch costs, enhancing units' flexibility, and promoting wind and solar energy consumption. Finally, combined with the actual power supply and heating in Zhangjiakou, China, the HPD effect in the area was analysed to provide guidance and suggestions for the flexibility retrofit of local thermal power plants.