Modelling and numerical solution of multibranched DC rail traction power systems

Based on the method of nodal voltage circuit analysis, a complex DC-fed traction power network with multibranched lines has been modelled. The model also incorporates detailed return circuits so that rail potentials can be calculated, a requirement which arises because of safety and stray current considerations. The introduction of branch joints and divided rail cells greatly increases the quantity of circuit nodes and gives rise to a large sparse conductance matrix. After establishing a set of simultaneous linear equations describing the behaviour of the network, consideration is given to the most suitable method of solution to prevent excessive computation times and storage requirements. Sample calculation results for train, substation busbar and branch joint voltages and currents are given, together with rail potential profiles