Study On Harmonicanalysisand Its Application Based On Simplify K-S Transform Algorithm

With the rapid development of the national economy,people's electricity demand is increasing.However,with the extensive use of non-linear loads in thepower network and the introduction of new energy sources,the problem of power quality(PQ)is increasingly serious,and it poses a threat to the safe operation of the power network.Affected by the electricity environment,the harmonic problem of the power networkis increasingly serious and complicated,the occurrence probability is getting higher and the influence range is getting bigger,and the harmonic pollution of power networkhasreceived more attention.The extraction of harmonic time-frequency parametercan provide important basis for harmonic power flow calculation,harmonic energy measurement and harmonic control.Therefore,the study of the new harmonic detection method,and the application which based on embedded modeis of great significancefor harmonic detection and improve of the harmonic.Firstly,this thesis introduces the definition,hazards and causes of the harmonic,and describes the present research status and development trend ofharmonic detection algorithm.This thesis also analyses the characteristics and shortcomings of different methods,especially the time-frequency domain algorithm.Secondly,this thesis introduces the S-transform,and briefly describesits advantages and shortcomings.Then,a new time-frequency algorithm which is developed based on the S-transform is introduced.By analyzing the energy time-frequency distribution of the time-frequency domain algorithm,an adaptive Kaiser window function is constructed,the Gaussian window used in the standard S-transform is replaced,and the K-S transform is obtained.The derivation of the algorithm is given,the characteristics of the algorithm are introduced,and the characteristics of the K-S transform are analyzed by simulation,which provides a basis for the application of the algorithm in harmonic detection.A harmonic detection method based on K-S transform simplification algorithm is proposed.The K-S transform is simplified by using the simplified idea in the detection method,which greatly reduces the actual computational complexity of the KS transform and uses the K-S transform simplification algorithm to detect the harmonic signals in a variety of cases to obtain the harmonic signal characteristic frequency point of the time-frequency vector,according to the results of time-frequency vector on the corresponding detection of harmonics.At the same time,under the influence of noise,the simulation results show that the detection error of the algorithm is small and the anti-interference is strong.Then,based on the proposed algorithm and the actual project,an embedded system based on ADC&DSP architecture is designed.The hardware and software design of embedded system is introduced in detail.The hardware part includes data sampling module,data processing module and so on.The software part is based on TI-RTOS,and the software design scheme,task assignment,scheduling and program execution process of the specific task of the harmonic detection module is introduced in the software part.Finally,this thesis analyses the reliability of the equipment and the actual test is carried out.The test results show that the overall design featuring stable and reliable and the system satisfies the requirement of harmonic detection.Above all,the platform and reference to resolve other PQ.