A Distributive Approach of Microgrid Control based on System Frequency

A Distributive Approach of Microgrid Control based on System Frequency

Ashil Thomas, A (TU Delft Applied Sciences)

Bauer, P. (mentor)
Izadkhast, S. (mentor)

Delft University of Technology

Electrical Engineering | Sustainable Energy Technology

CSGRiP

2017-08-30

The world at large is passing through a phase of energy transformation – from a traditional centralized unidirectional to a decentralized and distributed bidirectional power system, with consumers becoming prosumers. Facilitated by the technological advancements in power electronics and growing concerns over climatic changes, this transformation lead to increasing deployment of renewable energy sources. All these converge to the evolution of a concept – Microgrid, which empowers Smart Grid of the Future.

In the thesis, the concept of Cell, a microgrid comprising of Distributed renewable energy sources like solar, wind etc., Battery energy storage systems and Controllable loads is conceived. Devoid of use of any communication equipment, the Cell relies on measurements of local variables for evaluating the State of Energy and Power. The primary focus is on the formulation of control strategy based on droop control that enables a seamless (dis)connection of Cell with External Grid, with still maintaining the operation of converter in voltage source mode. This control scheme is further extended for connection and disconnection of multiple Cells interconnected through a Backbone bus, referred to as Interconnected mode. Adding to this, a decision-making algorithm is developed for an autonomous operation of Cells, that determines the switching instants between Stand-alone and Interconnected modes.

The developed control strategy and automated decision-making algorithm was simulated in DIgSILENT PowerFactory software for varied scenarios to evaluate the performance and the overall stability of the system. The simulations show a seamless transition between different operating modes – Stand-alone, Interconnected and Grid-connected and the automated decision-making algorithm succeeded in achieving overall stability, increasing the reliability of power to end consumers. Experiments were performed on a standard converter to prove the practical implementation capability of the developed control scheme as an intermediate interface. The modular and distributed nature of the developed controls and algorithm, makes it's advantageous to apply such Cells to electrify remote areas, which have limited or no access to power. The system can be easily scaled and expanded by adding more Cells, to build a strong and robust microgrid network.

Microgrid
Smart Grid
Distributed Renewable Energy Sources
Battery Energy Storage System
Droop Control
Voltage Source Converter
PowerFactory

http://resolver.tudelft.nl/uuid:cf589588-87c1-4445-8df8-a20bff3105e7

Student theses

master thesis

© 2017 A Ashil Thomas