Application And Research Of Frequency Control Technology In Supercritical Circulating Fluidized Bed Unit

In thermal power generating units,the important auxiliary equipment of the boiler system,such as primary fans,secondary fans and induced draft fans,are usually equipped with high-power motors,which are the main components of factory electricity.In recent years,high-voltage frequency conversion equipment has been widely operated in thermal power plants with its superior regulation performance,higher power factor and good energy-saving effects,and has achieved good results.This paper takes the selection of auxiliary equipment control schemes of2×350MW supercritical circulating fluidized bed units of Jiangsu Huamei Thermal Power Co.,Ltd.as the research object,and compares the common adjustment methods such as inlet adjustment,outlet adjustment and variable speed adjustment of the fan system.,Combined with the operating characteristics of the supercritical circulating fluidized bed boiler and the various requirements for load regulation,it is determined that the primary and secondary fans use frequency conversion control.The classification of high-voltage frequency conversion and the control model of the rotor flux are compared and analyzed,and it is determined that the voltage source type inverter is adopted,and the rotor flux adopts the voltage model.Aiming at the neutral point clamped three-level frequency conversion scheme and cascaded high voltage frequency conversion scheme,through theoretical analysis and MATLAB simulation comparison,the effectiveness and good waveform of cascaded high voltage frequency conversion scheme are confirmed.Through the selection and determination of the high-voltage inverter and the implementation of the specific plan,the inverter control plan,DCS logic design,and chain protection logic have been implemented in engineering.The energy-saving effect of frequency conversion adjustment and the circulating fluidized bed temperature are realized.The adjustment effect and the AGC tracking effect were analyzed and compared,and the predetermined design requirements were met.And through a failure analysis,it reflects the good adjustment characteristics and convenient maintainability of the high-voltage cascade inverter under the fault state,which can effectively improve the safety and stability of the supercritical circulating fluidized bed unit.Through the research of this article,it is further verified that the high-voltage frequency conversion technology is applied to the supercritical circulating fluidized bed boiler auxiliary equipment.It not only effectively reduces the power consumption of the auxiliary equipment,but also the unique rapid adjustment function of the frequency conversion technology.Further improve the regulation characteristics of the unit to ensure the safe and stable operation of the unit.This article has 75 figures,15 tables,and 96 references.