| In order to solve the problem of frequency fluctuation caused by the rapid increase of the proportion of new energy on the power generation side and the widening of the peak-valley difference of power consumption on the load side,it is urgent to explore more regulatory resources to enhance the consumption capacity of renewable energy and reduce the demand of rotation reserve capacity of the system.In recent years,related studies have shown that the flexible demand-side resource,thermostatically controlled load,can be applied to frequency regulated auxiliary services.However,the capacity of a single thermostatically controlled load is limited,so it needs to be aggregated into a larger capacity before it can be used for frequency regulation service,when studying its frequency modulation ability,the traditional equivalent ETP model does not consider the influence of external factors on the convergent power of temperature control load.The frequency regulation process of traditional generator sets lasts for a long time,and the thermostatically controlled load may cause power oscillation when it resumes operation after participating in the response.Therefore,the control time of the thermostatically controlled load also has a great influence on the frequency recovery process.In addition,considering that the thermostatically controlled load centrally participates in the whole process of frequency modulation through demand response,the problem of communication delay in each link is inevitable,which makes the load delay response and causes new power oscillation in the power system.Considering the accuracy of terminal measuring equipment with distributed control,the monitoring error of power system frequency fluctuation may cause overshoot or undershoot in response time.Based on the above background,the work content of this paper is as follows:(1)A typical thermostatically controlled load model was constructed,and the cluster of thermostatically controlled loads was incorporated into the now available power scheduling system.The representative thermostatically controlled load----air conditioning was taken as an example to study its operation characteristics and the influence of temperature set value adjustment and response scale on its regulation ability.(2)Equivalent simplified model and control framework of thermostatically controlled load group participating in primary and secondary frequency modulation of power system are established;Prolonged thermostatically controlled load centralized control of frequency modulation method is put forward,this method combines the priority control based on state transition time and changing temperature set point control,the advantages of can under the premise of considering the user comfort to extend the time of thermostatically controlled load of load control,reduce the temperature load in response to the possibility of a rebound after the peak,reduces the power oscillation;The simulation results show that the convergent air conditioning can provide primary and secondary frequency modulation services well,and the proposed control method can greatly extend the control time and reduce the load rebound peak after the occurrence of frequency response events.(3)Aiming at the existence of centralized control method in the communication latency and decentralized control method for the problem of frequency measurement error of the proposed a communication latency and frequency measurement error influence of thermostatically controlled load frequency regulation hybrid control method,this method is verified by the simulation can not only within a certain range lower limit to the requirement of communication time delay,It can also reduce the influence of overshooting or insufficient inaccurate frequency modulation caused by frequency monitoring error of distributed control method. |
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