Comparison of Grid-Following and Grid-Forming Control in Weak AC System

High-voltage direct current (HVDC) transmission has been in the past, and will be also in the future, widely applied in case that large amounts of electrical energy have to be transferred over long distance. However, the suitability of HVDC transmission depends also on the strength of the AC system. One of the various measures to achieve stable operation of HVDC converters connected to weak AC grids is the use of grid-forming control. The paper presents the results of a comparative analysis between three methods of grid-forming control and their applicability in a converter-based generation dominated HVAC network. After performing several EMT studies with generic models, the recommendation for the real transmission network investigated is an application of Virtual Synchronous Machine VSM control.