Research And Application Of Interharmonics Detection Algorithm Combined With Kalman Filter And AR Model

Electrified railway as a special part of electric power systems, is non-linear load in electric locomotive. Because of electric locomotive braking and acceleration when it running, tend to traction power supply system and the utility grid brings serious harmonic pollution. Now, researchers have to integer harmonics detection and analysis with a full understanding, but the non-integer harmonics of power grid——inter harmonics, the research is not deep enough. Inter harmonics is the same as harmonics, will do harm to the power equipment operation, the threat of traction power supply system itself security, and inter harmonics has the characteristics of random distribution, not smooth, easily affected by the weather and environment,previous detection method is difficult to measure the fast, accurate to the. To achieve fast and accurate interharmonic measurement is the basis for governance, so it has very important theoretical and realistic significance to study the inter harmonics detection.This article mainly from the standard IEC algorithm, based on the Burg algorithm of AR model algorithm, the AR model algorithm based on Kalman filter algorithm etc.of the algorithm research and implementation of traction power supply system based on inter harmonics. Fourier transform is the most fundamental harmonic and inter harmonic analysis method, which has been adopted by IEC 61000-4-7 and IEC61000-4-30 standards, the advantage of this algorithm is simple in calculation, good accuracy synchronous sampling; the disadvantage of it is that it exists the spectral leakage and fence effect. Modern spectral estimation method has the congenital superiority in random signal processing, can show the frequency characteristics of accurate. AR model in this paper first representative from modern spectral estimation in the beginning of the discussion, and then introduces the commonly used Burg algorithm, and the algorithm for the shortcomings of spectral line splitting and peak shift, proposed a new algorithm of inter harmonic detection combined with Kalman filter and AR model. The method uses Kalman filtering algorithm for AR modelparameter estimation, the AR model parameter vectors as state variables, the system state equation is established, and with the sampling data observation equation of the system was established, thus obtains the minimum variance parameter vector to establish estimation model. In making accurate spectral estimation based on the measured signal, further proposes the use of Kalman filtering algorithm for inter harmonic amplitude estimation and spectrum line interpolation correction method, the method using the Kalman iterative algorithm to the known frequency of inter harmonics accurately amplitude estimation, through the spectrum line interpolation algorithm for frequency and amplitude of each component is further modified, greatly improve the detection accuracy of interharmonics.Respectively in IEC standard conditions by means of Matlab simulation program,including noise IEC under standard conditions and non synchronous with noise IEC under standard conditions, through the Fu Liye transform method, AR model method of Burg algorithm and Kalman filter algorithm combined with AR model were measured on the same signal based on, through the analysis of experimental data show that the in this paper, the proposed method significantly improves the spectral estimation performance electric signals, can make the interharmonic spectral estimation, and has the advantages of strong anti-interference ability, high calculation efficiency, strong actual effect etc..Finally the power quality detection system for traction and analysis power supply equipment combined with the algorithm, developed with the function of detecting inter harmonics portable power quality detection system for traction and analysis power supply equipment, Using this prototype for Beijing railway bureau beijing-guangzhou route a certain traction substation has carried on the field experiment, the experimental results verify the effectiveness of the proposed method.