Enhancement of Controllability in Distribution Grid by Means of Power Electronics Components based Distributed and Centralized Solutions

The contemporary distribution grid is undergoing evolutions for the increased penetration of distributed generation and new types loads. Innovative operation schemes and components should be adopted to cope with the emerging grid issues. Exploiting power electronics (PE) components, operation approaches can address the issues. In this thesis, fast charging station (FCS), energy storage static synchronous compensator (ES-STATCOM), and smart transformer (ST), have been analyzed in the development of solutions to enhance grid controllability. A load-leveling approach has been proposed, using reactive power from the spare capacity of the FCSs, to regulate the grid voltage, eventually to shape the power demand of voltage-sensitive loads, tracking the demand forecast, reducing the mismatch, and keeping a satisfactory charging. This approach is a distributed solution since it coordinates the actuators spread geographically in the grid. A PE based approach employing voltage-correlation coefficients has been proposed to cope with voltage violation. For PE components such as ES-STATCOM and ST, the applied correlation coefficients must be adapted accordingly. Corresponding voltage regulation schemes have been developed. The analysis has illustrated the effectiveness of the proposed schemes and distinguished some significant differences between ES-STATCOMs and STs. The meshed grid configuration can offer more flexibility respecting the radial grid configuration. This work has proposed an ST based meshed grid operation approach as a centralized solution. An operation scheme has been developed, employing a multi-objective operation algorithm to address the emerging issues. Besides, a power quality conditioning scheme has been developed to condition the harmonics in current.