Harmonic evaluation of traction system by Monte Carlo simulation

This paper presents a method to predict the harmonic current level of traction system with phase-controlled DC motor drives by Monte Carlo simulation. Based on the behavioral modeling technique (BMT), a model for electrical unit of traction is proposed. The probability density functions (PDF) of speed and notch numbers are obtained from long-term field measurement. The mean and variance of harmonic current of a single electrical unit is obtained based on the speed PDF and traction electrical unit model. The results of Monte Carlo simulation are in good accordance with the experimental and analytical conclusions. The harmonics of a different number of trains are systematically investigated. It is shown the total harmonic distortion decreases with the increase of the number of trains and the harmonic current per train decreases with the train number because of the harmonic cancellation.