Load flow control and optimization using phase shifting equipment in combination with Banverkets rotating converters

The purpose of the thesis was to further investigate the possibility to complement the rotary converters with a phase shifting device as a continuation of the work done in the master thesis; Load flow control and optimization of Banverkets 132 kV 16 2/3 Hz high voltage grid. With this modification, rotating converters can be used almost as flexible as static converters. The earlier thesis has come to the conclusion that the best way of compensating the phase displacement is with a series inductance. In this thesis the possibility to use capacitors instead of or in combination with inductors was investigated. To investigate this three different models were built: One for the railway between Häggvik (Stockholm) and Boden; the same model that was used in the earlier thesis; it was used to confirm the results, one for the railway between Boden and Haparanda and one model that was the same as for the Haparanda track but half the distance. The models were built in the simulation program SIMPOW. The results from the simulations performed for the railway between Boden and Häggvik confirmed the results from the earlier thesis, with a series inductance as phase shifter. For the railway between Boden and Haparanda one phase shifting device consisting of reactors and one consisting of a combination of reactors and capacitors were dimensioned. The railway with half the length compared to the Haparanda track was used to see if the length of the track in a low impedance transmission system has a large influence of the size of the reactances needed. From the simulation the conclusion can be drawn that the track length does not have a large influence when suitable reactances are chosen. It is the size of the load and the phase angle that matter when choosing reactances. For the Haparanda track it is possible to save power. With a phase shifter that consists of reactors that is placed in the converter station in Kalix, power savings of 340 MWh/year were achieved. With a combination of reactors and capacitors with the capacitors in the converter station in Boden and reactors in the converter station in Kalix power savings of 750 MWh/year were achieved.