| With the continuous expansion of wind power in north China area,the wind abandon phenomenon in winter heating period becomes more and more serious.The reason for this is that under the traditional heating unit operation mode,the load of heating unit forced to be high to meet the need of heating network,which is called power is decided by heat.The space of wind power to participate in the grid is limited.When the wind power is superfluous,the heating unit cannot decrease the load to let the grid take wind power.In order to make heating unit suitable for participating in load peak regulation of grid,thermo-electric decoupling must be realized.In this paper,the thermodynamic analysis of heating unit is done.The thermal power unit model with heating extraction is built by analyzing the energy balance and mass balance of the heating extraction system.In the model the characteristic of LV valve and EV valve is considered,and a simplified mechanical model which is suitable for controller design is presented.The safe operation area of heating unit is calculated,and the cooperation between heating unit and heat storage device is analyzed.Based on that a characteristic analysis method of CHP unit with thermal storage device based on diagrammatizing is presented.The method can solve the setpoint and operation area calculation problem briefly.Considering that in China most of the heating extraction system is controlled manually by operators,an automatic control method of heating extraction system is designed.The control system consists heating extraction flow automatic control and heating network supply water temperature automatic control.The heating extraction flow automatic control is realized by periodic pulse method,and heating network supply water temperature automatic control is realized by open-loop control method based on water temperature deviation.The optimized control method is carried out in a 330 MW unit and has achieved significant practical effect. |
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