| In order to cope with the problems of energy consumption,increased carbon emissions and environmental pollution,it is necessary to develop renewable energy power based on wind and solar power.The fluctuating,intermittent,and inverse peak regulation characteristics of renewable energy power pose a huge threat to the stable and safe operation of the power grid.In the “three northern regions” of China,the heating period coincides with the period of more wind power generation,and the cogeneration units with a relatively large installed capacity will adopt the “following the thermal load” operation mode,which will further weaken the absorb of wind power in power grid.In order to alleviate the problem of wind power abandonment,this paper focuses on the cogeneration unit,and studies the use of energy storage on the turbine side to improve its rapid loadchanging performance,and configures additional heat sources to achieve “thermoelectric decoupling” to improve its deep peak load regulating performance.The peak load regulating range of a cogeneration unit is mainly limited by the thermal load.In order to solve the problems of heavy workload of traditional methods and the results deviating from actual working conditions,a method for predicting the peak load regulating range of the unit based on the least square support vector machine(LS-SVM)is proposed.After preprocessing the unit operating data,select a part of the data to establish a sample set to train the LS-SVM model,and then use this model to obtain the peak load regulating range under different thermal loads.The results show that the average relative errors of the maximum and minimum predicted power values based on LS-SVM are 1.00%and 1.25%,respectively.There is huge energy stored on the turbine side,when the unit is running,which can be quickly activated by condensate throttling to improve the rapid load change performance of the cogeneration unit.The static and dynamic models of condensate throttling were established through mechanism analysis,and a 350 MW cogeneration unit was chose as an example to simulate the rapid load performance of condensate throttling under different throttling flowrates and different operating conditions.The results show that when the electrical load is high(the thermal load is less),the load change performance of condensate throttling is better,and the increase of the throttling flowrate can also improve the load change performance.In addition,the load change performance of the unit is better,when is working under the sliding pressure operating condition.The maximum duration of condensate throttling is mainly affected by the condensate throttled flowrate,and the maximum 1-minute output power increment is between 4.972 and 22.999 MW.The cogeneration unit coupled with additional heating sources can enhance its peak load regulating capacity.The simulation model of a cogeneration unit including a thermal storage tank and an electric boiler was established,and the effects of their parameters and heating load on the peak load regulating depth and reserve power generation capacity are studied,moreover,the peak load regulating ability after parameter optimization was studied.The results show that this scheme can increase the peak load regulating depth and reserve power generation capacity,and the increase in reserve capacity increases with the increase of thermal load,but the increase in peak load regulating depth decreases first and then increases with the increase of thermal load.After the optimization,the power of the heat storage tank and the electric boiler are 117 MW and 70 MW,respectively.when the heating load is 66 ～ 300 MW,the output power of the combined system can reach “zero”.After the additional heating source is configured,the maximum peak load regulating capacity of the system is increased from 241.5MW to 334.7MW,with an increase of38.59%;the maximum heating capacity is increased from 358 MW to 545 MW,with an increase of 52.23%. |
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