Considerations of a shunt active filter based on voltage detection for installation on a long distribution feeder

This paper deals with a curious phenomenon referred to as the "whack-a-mole" that may occur in a long-distance distribution feeder having many capacitors for power factor correction. The whack-a-mole is that installation of an active or passive filter on the feeder makes voltage harmonics increase on some buses whereas it makes voltage harmonics decrease on other busses, especially at the point of installation. The distributed-constant circuit theory is applied to a simplified feeder in order to perform analysis of the whack-a-mole, thus reaching such an effective way as to avoid the whack-a-mole. Moreover, both theory and experiment clarify that installation of the active filter acting as a harmonic terminator on the end bus of the feeder can damp out harmonic propagation throughout the feeder without causing any whack-a-mole.