A comprehensive power quality conditioning system with energy storage for low voltage distribution networks

Tomasz Święchowicz

supervisor: Mariusz Malinowski

Technological advances in electric industry bring greater requirements regarding the quality of power in the grid and stability of the grid. These requirements are being enforced on industry and plans to extend them to private consumers may be ahead of us. Passive filters are common choice in the industry because of their low complexity, but they are limited to reactive power compensation and require individual selection of compensation blocks for each consumer. Active filters based on power electronics on the other hand offer flexible solution able to:

• compensate reactive power,
• balance active power between phases,
• compensate grid current harmonics,
• control active power flow if combined with energy storage or source.

The main objective of this thesis is elaboration of control method allowing simultaneous and selective operation of above functionalities. It should operate correctly with high grid impedance and capacitive loads. In case reference current could exceed converter ratings, these functionalities have to be linearly limited/disabled in prioritized order. Control algorithm allowing three first functionalities has been developed and is already sold in commercial product. Fig. 1 and Fig. 2 are waveforms taken by this device. Another objective is to enable operation of aforementioned control method on parallel connected power electronic converters with proprietary communication protocol that transmits data through high speed plastic optical fibers.