Load Modeling Of Beijing Metro And Analysis Of Its Influence On The Urban Distribution Network

With the rapid development of urban railway system, subway power supply system has become one of the important user of electrical power system, the subway load has become a special important load in the power system load. Because the subway load presents the characteristics of mobility, time-varying, nonlinear, make the existing methods can not calculate and forecast the subway load accurately. The purpose of this paper aims to establish the subway load model using the method of curve fitting, analysis the rule of the existing subway load, finally research the algorithm of the subway load forecasting, research on the influence of the subway load of urban distribution network.First, in this paper, the concept of the subway load was expounded. The characteristic of the subway load was analyzed. The parameters of load modeling was determine by studying the theory of subway traction load, the corresponding available data was obtained, the treatment method of the corresponding data was formulated, the function type of the fitting curve was determine after observation of change rule of the data curve,, and the expression of load curve was obtained by MATLAB program. And field test carried out was on the subway line one, and the feasibility of curve fitting modeling method was verified using with testing data which were de-noising processing using the method of wavelet analysis.Then, the algorithm of the subway load forecasting was studied. The testing valid data was sorted into daily load database, from the perspective of different substation, the feature of the daily load curve was analyzed, daily load curve model was got. In section reasonably, and the curve was fitted by using piecewise function; from the perspective of loads of two substations on same day, the relations between the daily load curves of two substations was analyzed, the regression analysis method is used to establish algorithm of load forecasting.Finally, the subway load effect on the urban distribution network was analyzed separately from medium voltage network and electricity consumption, harmonic analysis in three aspects. According to the power consumption analysis, the corresponding energy saving measures came up; according to the harmonic analysis, corresponding measures to suppress the harmonic were needed to take. From the load capacity of external power lines, the reliability of power supply,economy and harmonic suppression, discussing the program of voltage grade of the medium voltage network. Using the MATLAB software platform, the subway load analysis system was design, which can process and analyze the collecting load data.