The main grid supplies Svínoy, Viðoy, Borðoy, Kunoy, Kalsoy, Eysturoy, Streymoy, Vágar, Hestur, Nólsoy and Sandoy. The voltage levels in the main grid are 60 kV, 20 kV, 10 kV, 6 kV and 0.4 kV. The generation consists of heavy fuel oil, hydro power, wind power and biogas. A small development project with tidal energy is also in the main grid. An illustration of the power system is found on Figure 3.
In order to ensure the power quality and the security of the power system when introducing vast amounts of inverter-based production, a battery system of 12 MW and a synchronous condenser of 15 MVA will be installed at Sund Power plant in the spring 2023 and other batteries and synchronous condensers are planned elsewhere in the main grid in the near future.
100% Instantaneous Inverter-Based Generation in Suðuroy
The most southern island Suðuroy is a hybrid power system with heavy fuel oil, hydro power, wind power and photovoltaics. In addition to this a battery system and synchronous condenser have been installed, so that it is possible to run the system with 100% inverter-based generation whilst ensuring the stability and reliability of the system.
The wind power plant in Suðuroy was inaugurated in 2021, and an analysis of the frequency, shows that this has led to a wider distribution in the frequency, i.e. a higher standard deviation, as shown in Figure 2. The synchronous condenser and battery system were put into operation in the spring and summer of 2022, thus it will be interesting to see if these components will lead to a more narrow distribution in the frequency measurements.
Figure 2 – Probability density plot of the frequency in Suðuroy before (2018-2020) and after the wind farm (2021)