Abstract

In recent years, the integration of Renewable Sources of Energy in hybrid islanded grids has been significant, thus it is imperative to develop power control techniques to ensure the stable operation and reliability of system. In this diploma thesis, the structure of islanded grids and different control techniques has been presented.

In the first chapter a general description of hybrid grids, renewable sources of energy and the operation of diesel gensets is provided. Moreover, the primary load – frequency control is described.

The second chapter gives insight on more specific hybrid off-grid systems such as genset- photovoltaic-battery and genset-photovoltaic. For each system, various power control methods have been described.

Chapter three includes the presentation of the Real Time Digital Simulator (RTDS) which was used in all the experiments of this diploma thesis. The models that have been developed are genset with load, parallel operation of two gensets with load and genset with photovoltaic and load.

In the fourth chapter the genset-photovoltaic-load system was simulated in the RSCAD- RTDS and was controlled by a suitable controller (Controller Hardware in the Loop). Subsequently, a Power Hardware in Loop (PHIL) experiment is included where real laboratory loads were used as the hardware part. In this experiment the daily operation of hybrid islanded system was simulated, within the appropriate communication with SCADA systems.

Finally, conclusions are drawn and proposals for improvements and further work are presented.

Key words: Off-grid hybrid grid, primary load – frequency control, damp load, genset photovoltaic grid, real time digital simulator (RTDS), control hardware in loop (CHIL), power hardware in loop (PHIL), photovoltaic droop characteristic

Author: Nikos Ntavarinos

Responsible PhD: Panos Kotsampopoulos / kotsa@power.ece.ntua.gr

Supervising Professor: Nikos Hatziargyriou / nh@power.ece.ntua.gr

PDF: Full version (Greek) and Short version (English)