SoP Provide DSOs with an innovative solution for congestion management and fault location, isolation and supply restoration.


The SOP is made by two back-to-back three-phase power converters, allowing to decouple load flows and fault currents. Under normal conditions, it is closed thus creating a meshed/loop network topology and under fault conditions it opens to create a radial network topology (see Figure 1). 

Figure 1: The Soft-open point

Therefore, it provides the network operators with the following advantages:

  • Increased operational flexibility and hosting capability for distributed injections
  • Improved voltage profile (lower sensitivity to distributed injections), and load distribution (meshed/looped operation possible)
  • Innovative approach to solve upcoming challenges without jeopardizing existing network designs (e.g. Fault detection, isolation, and recovery (FDIR)) 
  • Can be integrated into other control approaches such as the GridEye approach


Preliminary Results

By the end 2017, the network model is established and the impact of SOP (voltage, SC level and protection) assessed (Attanasio et al, 2018) (Figure 2)


Figure 2: (left) Network model and impact assessment of SOP and associated conclusion on (right-up) the dependency of the current on SOP location and (right-down) the impact on the SOP on the voltage variation profile.

Based on this simulation, the SOP decreases the variation of the voltage along the feeder and the maximum current during the SOP operation is dependent on the SOP location.

Furthermore, the installation location has been re-assessed give that the network was evaluated as too strong and the space required too big to fit in the MV station initially planned.  

In terms of hardware, a small-scale prototype is already developed (Figure 3) (Attanasio et al, 2018).


Figure 3: Small-scale prototype of SoP

Involved partners/Contacts


Prof. Dr. Mauro Carpita (HEIG-VD IESE)

Prof. Dr. Patrick Favre-Perrod (HEIA-FR)


Attanasio, F., Schiesser, M., Gavin, S., Marchesoni, M., Favre-Perrod, P., and Carpita, M. (2018) Low voltage soft open point with energy storage: system simulation and prototype preliminary test results, submitted to SPEEDAM 2018 Symposium