Optimal Scheduling of Electro-Thermal Energy Integrated System Under the Background of Flexibility Retrofit of Thermal Power Unit

doi:10.12204/j.issn.1000-7229.2021.05.004

Abstract

Abstract:

For countries with a relatively high proportion of coal-fired power units, the implementation of flexibility transformation is one of the key means to enhance the flexibility of the power system. However, the role and operation mode of the system have changed after the unit transformation, and the original modeling method and scheduling strategy are no longer applicable. This paper proposes an optimized dispatching method for the electro-thermal energy integrated system considering the flexibility and transformation of thermal power differentiation. Firstly, the related technologies and characteristics of the flexible transformation of the two types of thermal power units are compared and analyzed. The apex-convex combination method is used to uniformly model the multi-stage peak shaving of the pure condensing unit and the multi-mode operation process of the cogeneration unit. Secondly, with the minimum total operating cost of the system as the objective function, and the electricity and heat balance, unit operation mode, unit climbing and start-up and stop as constraints, a mixed integer programming model for optimal dispatching of electro-thermal energy integrated systems is established. Finally, an example is used to verify the validity and applicability of the model. The results show that the model proposed in this paper can greatly improve the wind power accommodation capacity of the system, reduce the operating cost of the system, and can effectively reduce the peak load of the power grid in the "Three North" area.

Key words: flexibility retrofit, electro-thermal energy integrated system, optimal scheduling, mixed-integer programming

CLC Number:

TM721

XU Shanshan, GUO Tong, WANG Yue, LI Yonggang. Optimal Scheduling of Electro-Thermal Energy Integrated System Under the Background of Flexibility Retrofit of Thermal Power Unit[J]. ELECTRIC POWER CONSTRUCTION, 2021, 42(5): 27-37.

Figures/Tables 13

Table 1 Comparison of retrofit techniques for CHP units

Fig.1 Schematic diagram of CHP unit cutting off low pressure cylinder

Fig.2 Multi-stage peak regulation of a thermal power unit

Fig.3 Diagram of multiple operation mode of a CHP unit

Fig.4 Forecast data of load and wind power during heating period

Fig.5 Forecast data of load and wind power during non-heating period

Table 2 Comparison of annual costs under the three modes 万元

Fig.6 Thermal power of thermal power unit

Fig.7 Electric and thermal power of the same unit in three modes

Fig.3 Electric power of the thermal power unit and heat accumulator and electric power of electric boiler in mode 3

Fig.9 VRE reduction during non-heating period

Fig.10 Operation curve of thermal power unit

Fig.11 VRE reduction in five modes

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