For designing the AC filter in HVDC transmission project

this paper proposed a arithmetic based on time domain piecewise and Montecalo for AC side non-characteristic harmonic currents.Factors

such as imbalance of AC bus voltage and transformer impedance

non-uniform intervals of trigger pulse etc.

were comprehensively considered.The influence of DC side ripple currents on AC side harmonious currents was taken into account by considering overlap and non-overlap intervals respectively.In addition

statistic characteristic of equipment deviation and system imbalance were simulated by using Montecalo

and the non-characteristic currents injected into AC system were obtained.Taken a HVDC project as an example

PSCAD/EMTDC simulation was carried on

and the results were compared with those obtained by one time Montecalo calculating.