Optimal Operation of Multi-Terminal Soft Open Point to Increase Hosting Capacity of Distributed Generation in Medium Voltage Networks

A multi-terminal soft open point (MT-SOP) is a power electronic device, using multiple (3 or more) voltage source converters (VSCs) connected to a common DC busbar and multiple feeders, installed at previously normally open points in distribution networks. Due to its capability of accurate control of power flow, MT-SOPs are able to mitigate voltage and thermal constraints in medium voltage (MV) networks with high penetrations of distributed generators (DGs). The operating set-points were determined using a non-linear programming (NLP) optimization and a Jacobian matrix-based sensitivity analysis. The methodology was demonstrated on an 11 kV test network. Results showed that a three-terminal SOP reduces the network energy losses and enables the distribution network to host a further 20% of DG compared to a two-terminal SOP.