计算高压直流输电线路等效干扰电流的一般性方法(英文)

As a critical part in the DC filter design,it is very important to quickly and correctly calculate the equivalent disturbing current.A general method for calculating the equivalent disturbing current of high voltage direct current(HVDC) transmission lines is proposed.In this approach,one 12-pulse converter was represented by four 3-pulse harmonic voltage sources in series,the DC network was described by a multi-phase coupled transmission line model,and the harmonic currents of certain frequency were solved based on the basic nodal analysis method.The multi-phase coupled transmission line model was described briefly,which could treat DC transmission lines of any structure,e.g.one or two DC circuits in a tower.The harmonic voltage source calculation steps were outlined,the steps to form the nodal admittance matrix were discussed,and the equations to calculate the equivalent disturbing current of the DC line were given.To verify the general applicability of the suggested approach,two different HVDC projects were studied:a traditional single circuit HVDC project,and a newly constructed HVDC project with double circuits on a same tower.The results show that the proposed method can calculate the equivalent disturbing current of the above two projects effectively,and has obvious advantages such as easy implementation,fast calculation and wide applicability.According to the two cases,the distributions of the equivalent disturbing currents along the line have the same trend,i.e.,the maximum value of the equivalent disturbing currents appears at the line inlet of both sides.Plus there is no fixed relationship between the equivalent disturbing currents and the HVDC line structures,because the equivalent disturbing current depends on many factors,such as background harmonics and converter transformer parameters.

General Method for Calculating Equivalent Disturbing Current of HVDC Transmission Lines