Load Harmonics Analysis & Simulation Of Different Work Conditions Based On Locomotives

Electrified railroads in our country have quickly developed in recent years and have amounted to 30% of whole railroads. The electrified railroads that undertake 50% of total transportation bring a great benefit to national economy. However, a large amount of harmonic is generated in the power network when the electrified railroads loads consume fundamental frequency electric power. These harmonics make bad effect on the operation of protection relays and the precision of electricity measures, worsen the power quality and threaten the security of traction substations as well as other equipments in power system.It is necessary to study the mechanism of harmonics generation, make sure the content and distribute of harmonics current in order to alleviate their harm to traction power system's component, equipments of protect and measure as well as other customer's electronics equipments. Besed on the circuit, electromagnetism and electric power electronics theories, we have done some theory research on the harmonics induced by thyristor commutate circuits of AC-DC locomotive, surge electromagnetism process. We calculate the theory content of harmonics using the Fourier arithmetic under thyristor commutate and surge electrmagnetism process. In order to study the electrical traction load's harmonics, the thesis establishs the power supply network-locomotive model, and simulates several typical work conditions of traction power system with AC-DC locomotives utilizing the MATLAB/ Simulink tools. The magnitudes of harmonics have been gotten in several different work conditions and their correctness has been proved by comparison with the results from the field records measurements.This thesis also carries digital simulations of AC-DC-AC locomotives with actual parameter of locomotive using MATLAB/Simulink. The load harmonics characteristics of AC-DC-AC locomotives are presented, whichwill be helpful for the development of feeder protection relays of traction power system with AC-DC-AC locomotives.