Traction system scheduling to minimize harmonic current level at substation by genetic algorithm

Harmonics of individual trains are closely related to its loading, speed and operation mode. The harmonic current at substations is the sum of the individual components from all the trains electrically connected to the substation. There will be cancellation of the harmonics if the harmonics are not of the same phase angles. It is possible to schedule the traction system so as to minimize the harmonic distortion, improve the power factor and reduce the harmonic currents at substations. In this study genetic algorithm (GA) is used to find out the optimal schedule of the system with minimum harmonic levels. The optimized solution can be integrated into automatic train operation (ATO) controller to control the departure, speed regulation of each train of the system. Mathematical description of the problem is first presented and the genetic algorithm is introduced. The optimal solution is given at the end of this paper. It is demonstrated that the scheduling of traction system is applicable to harmonic reduction and GA is fit for such kinds of optimization problems. Such method of harmonics reduction can bring about considerable saving in filtering equipment