A controller implemented method for designing a multiple tuned filter, MTF, configured to filter harmonic components in a high voltage direct current, HDVC, system, the method comprising: setting (S510) an input parameter corresponding to the MTF, wherein the input parameter includes one of a rated voltage of the HVDC system, a reactive power to be compensated by the MTF, and a filtering harmonic component frequency to be filtered by the MTF; setting (S520) a resonance frequency of the MTF based on the frequencies of the harmonic components to be filtered; computing (S530) capacitance values of capacitors, C, of the MTF and inductance values of inductors, L, of the MTF that are matched to the resonance frequency of the MTF to obtain LC combination cases of the MTF; identifying (S540) filter impedance characteristics of the computed values of L and C and storing (S550) the values of the corresponding LC combination cases; computing (S560, S610) a first objective function (F1) having a total harmonic distortion (THD) as a minimum and computing a second objective function (F2) having a total demand distortion of current (TDD) as a minimum, for each of the obtained LC combination cases; respectively applying (S560, S640) preset weighted values to the computed first and second objective functions (F1, F2), wherein the preset weighted values comprise a first weighted value (W1) depending on a harmonic voltage regulation value applied to the first objective function (F1) and a second weighted value (W2) depending on a harmonic current allowable level applied to the second objective function (F2), wherein the first and second preset weighted values (W1, W2) are bigger than zero and smaller than 1 and are set to be varied ; and extracting (S560, S640), from the obtained LC combination case, an optimal LC combination case, for which a sum of the first and second objective functions, to which the respective weighted values are applied, has a minimum value. setting (S510) an input parameter corresponding to the MTF, wherein the input parameter includes one of a rated voltage of the HVDC system, a reactive power to be compensated by the MTF, and a filtering harmonic component frequency to be filtered by the MTF; setting (S520) a resonance frequency of the MTF based on the frequencies of the harmonic components to be filtered; computing (S530) capacitance values of capacitors, C, of the MTF and inductance values of inductors, L, of the MTF that are matched to the resonance frequency of the MTF to obtain LC combination cases of the MTF; identifying (S540) filter impedance characteristics of the computed values of L and C and storing (S550) the values of the corresponding LC combination cases; computing (S560, S610) a first objective function (F1) having a total harmonic distortion (THD) as a minimum and computing a second objective function (F2) having a total demand distortion of current (TDD) as a minimum, for each of the obtained LC combination cases; respectively applying (S560, S640) preset weighted values to the computed first and second objective functions (F1, F2), wherein the preset weighted values comprise a first weighted value (W1) depending on a harmonic voltage regulation value applied to the first objective function (F1) and a second weighted value (W2) depending on a harmonic current allowable level applied to the second objective function (F2), wherein the first and second preset weighted values (W1, W2) are bigger than zero and smaller than 1 and are set to be varied ; and extracting (S560, S640), from the obtained LC combination case, an optimal LC combination case, for which a sum of the first and second objective functions, to which the respective weighted values are applied, has a minimum value. <EOS>