Unified optimal design of filter at AC and DC sides of high voltage direct current transmission system

Filter design is one of the key technologies of high voltage direct current (HVDC) transmission system, but the traditional method processes filter design of AC and DC sides respectively and doesn't consider the harmonic interactions between AC and DC sides. The unified harmonic load flow algorithm was used and it was proposed that the filter design of AC and DC sides together and calculation of harmonic load flow were crossed and repeated. An integrated mathematical model for filter design was established, in which both the economic effect of the investment and the economic effect of year operation expense were considered, and then the genetic algorithm was used to obtain an optimal design scheme under the constrain conditions of the technology indexes. Moreover the method was used to design filters of a ± 800 kV UHVDC transmission system, and the correctness of the method for filter design was verified by the calculation result.