As an important equipment of converter station, DC filter is installed between DC high voltage bus and neutral bus, which is the most effective means to suppress DC harmonics in HVDC. The DC filter plays an important role in the safe and stable operation of DC transmission system.
Each converter station is equipped with two sets of three tuned TT 12/24/36 passive filters, and each filter has two identical control protection devices.
High voltage capacitor, high voltage reactor, low voltage capacitor, low voltage reactor and other parts compose the DC filter. According to the protected object of DC filter, differential protection and detuning protection are set for the whole filter. Unbalanced protection, overload protection and bridge differential overcurrent protection are set for high voltage capacitors. Reverse time overcurrent protection is set for high voltage reactors. Overload protection is set for low voltage resistors / reactors.
