Soft Open Point (SOP) is a fast-acting FACTS device developed to link two different medium voltage circuits, with the same or different voltage levels, phase angle or even frequency.
It manages bidirectional power flows whilst permitting their voltage or power factor to be controlled separately, which increases power capacity without traditional reinforcement. Each system is composed by couplings transformers and AC-DC-AC power converters built upon a back-to-back topology. SOP can reduce or eliminate the impact of faults reducing the SAIDI and SAIFI figures.