Fixed-frequency operation of an island grid with multiple grid-forming inverters and GPS-based synchronisation ...

• Main Authors: Strunk, Robin, Reus, Lucas, Hofmann, Lutz, Mertens, Axel
• Format: Book Part
• Language: English
• Published: [Stevenage, Hertfordshire, UK] : IET 2023
• Subjects: Fixed-frequency operation; Grid-forming inverters; Island power system; GPS-based synchronization; active power-angle droop; 600 Technik::620 Ingenieurwissenschaften und Maschinenbau::621 Angewandte Physik::621,3 Elektrotechnik, Elektronik; 600 Technik::620 Ingenieurwissenschaften und Maschinenbau; Faroe Islands; Suðuroy
• Online Access: https://dx.doi.org/10.15488/18939; https://repo.uni-hannover.de/handle/123456789/19084

By using an external signal for the synchronisation, an island grid with grid-forming inverters (GFMs) can be operated at a constant frequency. The global positioning system (GPS) provides a periodic pulse with a suitable accuracy. This is used to define the grid frequency and a reference for the voltage phase angle. A digital counter in the control hardware determines the phase angle. The counter is reset by each pulse of the GPS. An active power-angle droop control leads to partial power sharing between the GFMs and reduces distortions caused by non-ideal synchronisation. Furthermore, the grid operator can adjust the voltage reference phasors of the GFMs to control the power flow in the grid. An island grid with two GFMs and a hydro power plant is studied in simulations. The investigated power system is an altered and simplified grid model of Suðuroy, in the Faroe Islands. The effects of a load connection and a distorted GPS synchronisation are studied. Stable operation of the power system using the ...