Capacitive power factor and power quality correction of a light rail transportation system

This paper discusses an application of a method for dynamic power factor correction and voltage regulation in light rail transportation systems. The MV underground power cables installed for the distribution of 34.5 kV power substations cause a very poor capacitive reactive power factor. The technical specification of the customer was based on the dynamic compensation of the consumed electrical energy and to balance capacitive reactive power of all the MV cables and dynamic train effects. Inductive and capacitive kVArh values should not exceed the limits to avoid any penalty. Another aspect of the problem was that of voltage stability. The powers and the power factor have been analyzed. It has been concluded to install iron core reactors. Main reactors have been switched on through thyristors using automatic power controllers by sensing the power factor and constantly monitoring the current and voltage, calculating the power factor and switching inductance banks as required. The solution satisfied safely the penalty limits of the local utility.