Series compensation for increased power transmission capacity

For transmission of large amounts of electric power, AC in the overwhelming majority of cases is the established as well as the most cost effective option at hand. Series compensation, likewise, is an efficient means for minimizing the amount of transmission lines needed for a certain power transmission capability of an inter-connector. With series capacitors, the capability of already existing power lines can be increased considerably, thereby decreasing the need for building new lines in cases where the need for power transmission capability in a system is growing. Installing series compensation is typically also less costly as well as less time consuming than building new lines. The paper presents some basic mechanisms for series compensation in power grids, fixed as well as thyristor-controlled, some salient design features as well as operational experience for improving interregional power transfer in a cost-effective and environmentally friendly way.