Error Analysis and Correction of the Fluctuation Quantity-Based Method in Harmonic Impedance Identification for Traction Power Supply System

The fluctuation quantity-based method has been widely used because of its simple principle and strong practicability. However, when the harmonic source of the system side fluctuates greatly, the method has a large error. Therefore, in order to accurately evaluate the calculation error of the fluctuation quantity-based method and explore the applicability of the fluctuation quantity-based method, this paper takes the V/v wiring transformer as an example to propose the phase-to-phase harmonic transmission formula of the traction power supply system, and derives the error coefficient of the system harmonic impedance of the calculation by the volatility method. The results show that the calculation error of the fluctuation quantity-based method cannot be neglected. Therefore, an error compensation scheme based on genetic algorithm to identify the impedance parameters is proposed. In order to verify the correctness of the proposed theory and scheme, this paper establishes the simulation model of V/v wiring traction power supply system and conducts the computer simulation analysis. The results show that the error coefficient can accurately reflects the relative error of the fluctuation quantity-based method, and the scheme has good reliability and practicability.