Integrating black start capabilities into offshore wind farms by grid‐forming batteries

Abstract

Power systems are currently experiencing a transition towards decarbonisation through the large‐scale deployment of renewable energy sources. These are gradually replacing conventional thermal power plants which today are the main providers of black start services. Consequently, in case of a total/partial blackout, conventional black‐start resources may not be ready for operation. Offshore wind farms (OWFs), with their large capacity and fast controllers, have potential as innovative black‐start units, thus, the need for a new design for OWFs. Here, challenges and possible solutions in integrating black start services into offshore wind farms will be presented. The first challenge is represented by the self‐start capability. The self‐start unit should be capable of forming the wind farm power island and withstanding transient phenomena due to the equipment energisation. The investigated solution comprises grid‐forming (GFM) converters in the wind farm design, which could be battery energy storage systems (BESSs) to also increase the service availability. The challenges are analysed using simulations on a wind farm, and the proposed solutions are discussed. It can be concluded that a hybrid system comprised of a BESS and an OWF, with GFM control, applying soft‐charging, etc., represents a good proposal to provide black start services by OWFs.

Challenges and potential solutions of grid-forming converters applied to wind power generation system—An overview

“…However, the island operation or black start of the GFL-based wind generator is a challenge. A possible way is to make use of the BESS for black start (Pagnani et al, 2022). Namely, during the black-out, the BESS with GFM control in Figure 2C is used to establish the local grid voltage.…”

Black-start of microgrids: Insights based on demonstration sites in Europe and India

“…During the procedure of power restoration, the system will be comprised of several dynamic microgrids, where the boundaries would vary depending on the requirements of the system operator. In [8], a grid-forming BESS is used to energize an offshore wind farm in several steps: 1. Energizing the wind farm (soft start strategy); 2.…”

Optimal sizing of battery energy storage to enable offshore wind farm black start operation

“…To reach net-zero emission in 2050 as per the Paris Agreement, renewable energy sources (RES) are being installed, whereas conventional plants decommissioned. Therefore, the overall behavior of the power system is becoming more unpredictable, increasing the risk of blackout in the power system [2]. Once a blackout occurs, the power system restoration has three steps: black start, network reconfiguration, and load restoration [3].…”

“…To deal with this problem, RES can take a major role in providing black start services, particularly large offshore wind farms (OWFs). Nowadays, there are no black start units from RES, but the large capacity and the short start-up time of OWFs seems an attractive solution [2], [4], [5]. However, OWFs may need extra help to satisfy all black start technical requirements defined by transmission system operators (TSOs) [1], [2].…”

“…Nowadays, there are no black start units from RES, but the large capacity and the short start-up time of OWFs seems an attractive solution [2], [4], [5]. However, OWFs may need extra help to satisfy all black start technical requirements defined by transmission system operators (TSOs) [1], [2]. In fact, wind power fluctuations caused by wind speed variability result in serious concern about the reliability and satisfactory operation for black start capability.…”