Analysis of Demand Factor for High Speed Railway Power Transmission Line from Load Measurement Data

Abstract

With the rapid construction of high-speed railway in China and other developing countries, as well as the continuous expansion of its distance and scale, the load of power transmission line along the railway is increased accordingly. However, the existing design standards for power transmission line of high speed railway cannot specify the demand factor for the electrical load supplied by power transmission line, and there is no unified calculation method for the demand factor, resulting in a large difference between the theoretical value and the actual value of transformer capacity and cable section selected for engineering project, which takes huge additional energy penalty from the utility companies. To address the problems and formulate a more accurate selection standard for the load demand factor of high-speed railway power transmission line (HSR-PTL), the demand factor is calculated from the data measured on several typical high-speed railway operating in China. Firstly, the load model of HSR-PTL is proposed. According to the function and characteristics of the several kinds of load in HSR-PTL, each load is classified for load demand modelling. By measuring the load of several typical operating HSR-PTL, based on the proposed model, the value of the required coefficient of each load type based on the measured data is proposed. The calculated demand factor can be applied as an applicable reference for the design of high-speed railway power system.

Identification of Voltage Sag Sources in the Electrified Railway Power Supply System Based on CNNs

“…Xiong and Yang proposed that in the actual power grid, the reasons for the formation of voltage sags are complex, and the waveforms of various voltage sags are different. Under normal circumstances, when there are events such as lightning strikes or the startup of highpower equipment in the power grid, voltage sags can be caused [2]. Kumar et al said that voltage sag sources can be divided into single-voltage sag sources and compoundvoltage sag sources [3].…”

“…Usually, in the reactive power detection of negative sequence and harmonics, it is necessary to do the following: (1) in the operation of the railway and highway controller system, it is not necessary to undertake all the reactive power compensation, but in the separate reactive current inspection, the superposition processing of the active current reduces the load current of the power supply arm, so as to obtain the final negative sequence harmony wave reference value. (2) In the analysis of the load current of the power supply arm, multiply it by the π/2 signal of the voltage of the y arm, and the peak value of the product of the load current of the power supply arm and the π/2 signal of the voltage will appear, and in the case of the low-pass filter being DC, it is subjected to shunt filtering. (3) In the case of reactive current at both ends of the system, it is necessary to adopt the reactive power detection technology of negative sequence and its own harmonics, and through the processing of DC and component filtering, the filter compensation amount and the negative sequence compensation amount can be eliminated and provide data support for the highquality operation of the system.…”