ACTIVE DC FILTER FOR HVDC SYSTEM - A TEST INSTALLATION IN THE KONTI-SKAN DC LINK AT LINDOME CONVERTER STATION

The purpose of introducing active dc filters is to meet the more and m ore stringent requirement from power utilities on limiting telephone i nterference caused by harmonic currents from HVdc transmission lines, without unnecessarily increasing the cost of HVdc stations, An active dc filter installed in the Konti-Skan HVdc link is described. The acti ve dc filter is connected at the bottom of an existing passive dc filt er at the Lindome station. The active dc filter includes optic harmoni c current measuring unit, control system, protection and supervision s ystem, PWM power amplifier, high-frequency transformer, surge arrester , and coupling apparatuses. The active dc filter has small physical si ze and occupies small ground area. The performance of the active dc fi lter for eliminating the disturbing harmonics is excellent. To achieve comparable results by passive filters would require something like te n times more high voltage equipment.