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. Static VAR Compensators are common choice in the industry because of their low material cost, but they are limited to reactive power compensation and require individual selection of compensation blocks to match given consumer needs. Power electronic counterparts on the other hand offer flexible solution able to:

• compensate reactive power,
• symmetrize 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. In case of reference current exceeding converter ratings, these functionalities have to be linearly limited/disabled in prioritized order. Control algorithm allowing three first functionalities has been developed in the recent year and is already implemented in commercial product. Another objective is to enable operation of aforementioned control method on parallel connected power electronics converters. The lack of a standard high-speed communication system enabling synchronization requires the development of a tailor-made system.

Fig. 1 Converter turned off.


Fig. 2 Converter turned on.