ITERATIVE TECHNIQUES FOR THE SOLUTION OF COMPLEX DC-RAIL-TRACTION SYSTEMS INCLUDING REGENERATIVE BRAKING

The solution of simultaneous algebraic equations describing a DC-tract ion power system is based on an iterative technique because of their n onlinearity. Two iterative methods specified for DC-load-flow problems are described and their mathematical and geometrical explanations are presented. The methods have been tested for DC-fed traction power sys tems and comparisons made of the computational time and iteration coun t. The DC-traction software which has been developed enables the situa tion with trains operating in regenerative-braking mode to be simulate d. A condition in which convergence problems are to be expected occurs when there is a surplus of power produced during regenerative braking . In this case two different modelling approaches to represent regener ative trains in the simulation are investigated. A representative DC-f ed-traction power system with train regenerative braking was simulated and the preferred method is selected by analysing the simulation resu lts obtained and the computation times expended.