Parallel AC/DC transmission lines steady-state induction issues

Steady-state induction at fundamental-frequency into an HVDC transmission circuit from parallel AC lines can lead to several adverse impacts on system performance. Based on a generic analysis of the impact on converter performance, a threshold of 0.1% fundamental-frequency ripple on DC current is established as a point beyond which detailed studies of the effect on converter performance should be required. Guidelines are provided for the calculation of steady-state induction to the DC converters, which should be carried out if significant exposures exist. Should steady-state induction exceed a threshold beyond which the converter can operate satisfactorily, several mitigation options exist