Abstract-Two novel power flow controller topologies are proposed for flexible AC transmission systems (FACTS). The first one consists of a shunt connected source of reactive power, and two series connected voltage-sourced converters -one on each side of the shunt device. The second topology is a dual of the first; it is based on two shunt connected current-sourced converters around a series connected reactive element. In both cases the converters can exchange active power through a common DC circuit. Both topologies make combined use of passive components and converters and can therefore be regarded as hybrid. Employing hybrid topologies enables use of converters to enhance the functionality of existing equipment in a power system. The paper demonstrates that, by using appropriate converter additions and control, the functionality of switched shunt or series capacitors can be enhanced to generalized power flow control -a functionality commonly associated with the UPFC. Since existing equipment is fully utilized, the hybrid topology requires considerably lower total converter ratings compared to the UPFC
