Highpass filter of a filter arrangement for a three- phase network connected to converters

Abstract From the Canadian patent

For reducing the amount of circuitry and losses in double highpasses for filter arrangements in networks with a high voltage level, the two resonance frequencies and Q-factors of the double highpass are tuned so that in a critical harmonic range, at most a harmless slight resonance peak can occur for, which purpose a series capacitor together with a series choke are connected in series with a shunt circuit grounded in the, case of high voltage and ungrounded in the case of medium voltage, of ohmic, inductive and capactive circuit elements connected to the network.