Blog #7

Resilient microgrid platform at KTH

Lars Nordström – KTH, The Royal Institute of Technology

Microgrids are building blocks of future smart grids, as key enablers for renewable energy integration, smart community deployment and grid resilience enhancement. With the increasing penetration of DC sources and DC loads and to be compatible with the existing grid, hybrid AC/DC microgrid community is recognized as the operation paradigm for future distribution networks. However, there are many challenges in the future power systems, including the critical demand-supply power balance under the intermittent renewable generations, the economic operation under renewable uncertainties, the stability and reliability issue emerged from the high penetration of power electronic converters, the cybersecurity issues, and etc. To deal with these challenges, KTH is developing its resilient microgrid laboratory at KTH for advanced research and education. The ambition being to include research projects as well as training for all levels of students including life long learning and continuing education.

Hardware and communication system

The resilient microgrid consists of a a scalable hybrid AC/DC microgrid platform consisting of renewables (solar PV), battery, distributed generator and customer loads. The IoT enabled communication network is integrated for real-time communication and control, as illustrated in Fig. 1.

Fig. 1
Communication network

Fig. 2
The developed hierarchical control platform

Hierarchical control platform

A hierarchical control platform is developed in the cloud for stable, reliable and cost-effective operation, as shown in Fig. 2. In primary level, local controllers are embedded in local converters to achieve real-time balance and autonomous operation even without the communication system. In secondary level, we develop a series centralized and distributed control strategies to enhance the power quality with accurate tracking of voltage, frequency and power. In tertiary level, we develop a distributed and robust energy management system to achieve optimized operating cost of single microgrid and optimal energy sharing among microgrids, considering uncertainties and network constraints with guaranteed information privacy and plug and play characteristics. We also develop novel module-based stability assessment algorithm and hierarchical reliability assessment tool to guarantee overall system stability and reliability. More studies will be investigated on this platform in the future, e.g. cybersecurity, market, protection, etc.

It is one of our constructive steps towards the decarbonization and digitalization of energy sector at KTH.