Optimal Decentralized Voltage Control for Distribution Systems with Inverter-Based Distributed Generators

Abstract

The increasing penetration of distributed generation (DG) power plants into distribution networks (DNs) causes various issues concerning, e.g., stability, protection equipment, and voltage regulation. Thus, the necessity to develop proper control techniques to allow power delivery to customers in compliance with power quality and reliability standards (PQR) has become a relevant issue in recent years. This paper proposes an optimized distributed control approach based on DN sensitivity analysis and on decentralized reactive/active power regulation capable of maintaining voltage levels within regulatory limits and to offer ancillary services to the DN, such as voltage regulation. At the same time, it tries to minimize DN active power losses and the reactive power exchanged with the DN by the DG units. The validation of the proposed control technique has been conducted through a several number of simulations on a real MV Italian distribution system.

Nevertheless, the connection of DGs to DNs poses well-known technical challenges for the network management. Among them, voltage rise represents one of the main issues concerning DG integration into DNs , especially in the case of nonprogrammable RES-DGs (e.g., wind- or solar-based ones) in weak DNs, characterized by a small value of reactance versus resistance ratio.Thus, the necessity to develop proper control techniques to ensure power delivery to customers in compliance with PQR requirements and to furnish ancillary services to the network is becoming a relevant issue