Hierarchical reactive power regulation strategies for high-penetration photovoltaic distribution systems

Summary This paper proposes a hierarchical reactive power regulation system for distribution systems with photovoltaics (PV) connected. The proposed approach includes both central control level and local control level for decisions involving optimal reactive power compensation and dynamic control of reactive power regulation, respectively. Through local control level, based on the PV inverter controllers and central control level compensation command, the overvoltage and voltage variation problems can be highly relieved. In addition to possible reductions in PV generation curtailment, the grid voltage can also be well regulated with minimal line loss via the proposed PV system operation strategies. Accordingly, added value for PV systems is created, conferring win-win solutions for both PV system owners and utilities. Numerical results tested on a practical Taipower company distribution system verified the proposed approach.