Study on parameters of double tuned filter in HVDC transmission system and its simulation

It is recommended to use the double tuned filter in HVDC(High Voltage DC transmission)systems to suppress harmonic currents produced in conversion equipments.Its characters are discussed and its parameter design is presented:the series loop capacity can be deduced by solving the fundamental wave reactive compensation formula;the series,shunt inductance and the shunt capacity can be determined by the relationship of the resonance frequency and parameters.Formulas for calculating resonance points from filter parameters are deduced,and the significance of filter's being slightly inductive at tuned frequency is emphasized.At the same time,a safety coefficient is introduced.An example of filter parameter calculation is given and also simulated with Matlab / Simulink.Results show that,considering the system frequency deviation and avoiding its shunt resonant with the system,the safety coefficient is selected from 1.0 to 1.1 to obtain the better filtering effect.