Volt/Var Optimization with Minimum Equipment Operation under High PV Penetration

High penetration of photo-voltaic panels (PVs) in the distribution networks causes volatile net load profiles. In turn, voltage control devices (switched capacitors, on-load tap changers (OLTCs) and voltage regulators) work more frequently to keep voltage on distribution feeders within limits. This paper employs the most recently developed mixed-integer programming (MIP) modeling methods to model discrete control devices including OLTCs and switching capacitors for volt/var optimization to explicitly count mechanical switching actions. Further, coordination capability is explored to demonstrate that the use of PV VARs can effectively reduce operations of OLTCs and switched capacitors while obtaining a satisfactory voltage profile. Case studies are performed on the IEEE 33-node distribution feeder with 125% PV penetration.