The most basic SSN separation we can make to use the SSN method is to use the filter bank connection point as an SSN node. Consequently, we need to understand the causality of the groups we are going to define from this (3-phase) node.
The transformer has an inductive impedance as seen from the SSN node.
The source also has an inductive type impedance.
Finally, the filter group has a capacitive impedance as seen from the SSN node because one of its components is a simple capacitor.
The SSN method was applied here only to the rectifier side of the HVDC system.
The inverter side is still simulated by standard state-space method of SPS/ARTEMiS. The SSN can be applied also to the inverter side.
Using the filter connection point as a node, we end up with 3 SSN groups, shown below.
