Linearised direct harmonic solution method for a back-to-back HVDC link

This paper presents a linearised direct harmonic solution for a back-to-back HVDC link operating in the steady state. Using perturbation analysis, small signal distortions are applied to each converter using a time domain model. This allows the transfers around and through the converters to be linearised around a base operating point. The transfers are then written in nodal form and combined with the system equations to form the HVDC link linearised tensor admittance matrix. The system can then be solved directly for any applied distortion and used to determine transfers through the link.