Robust voltage regulation for active distribution networks with imperfect observability

This work targets voltage regulation in active distribution grids with imperfect observability due to limited communication and sensor equipment. Specifically, the on-load tap changer (OLTC) of distribution transformers, available voltage regulators, and few nodal reactive power injections are to be controlled in the presence of uncertainty about other nodal injections or voltage levels. The problem is solved with a novel two-stage, robust control approach for static linear systems with measurement-dependent uncertainty sets. The proposed ideas are demonstrated on small test feeders where OLTC positions are controlled based on local power flow measurements. More complex settings with additional sensors and actuators as well as robustness against a small number of significantly disturbed measurement signals are also shown. Results for the IEEE 123 test feeder prove the applicability to larger systems.