Definition of a Voltage-Source Converter dc-side admittance and its impact on dc-network stability

Paper i proceeding, 2015

The aim of this paper is to provide a definition of a parameter that can be used for the study of the dc-network dynamics in VSC-HVDC systems. Through an appropriate selection of subsystem within a point-to-point VSC-HVDC system, a dc-side power dependent admittance is defined. The particularity of this admittance is that, if negative, there is a risk that a dcside resonance becomes amplified. The dc-side power dependent admittance is measured in a EMT model and compared with a linearized mathematical model, showing good agreement between them. The usefulness of the defined admittance is shown through the assessment of various controller modifications on the dcnetwork stability enhancement. Finally, the conclusions from the analysis are verified through time domain simulations.