Optimal operation of the Swedish railway electrical system

Along some railway lines in Sweden, 130 kV transmission lines have been built and connected to the contact lines through transformers. With the present characteristics of frequency converters, injected active power cannot be controlled. To overcome this drawback, control of the static converter active power is studied. With this control, the active power injections can be adjusted to minimize the operation cost of the system. To calculate the optimal active power settings, an extended linear programming based optimal power flow algorithm has been tested. In this article, a brief description of the problem of optimizing the operation of the Swedish system is given. To demonstrate the different parts of the problem, examples are given