Offshore Wind Farm Black Start Service Integration: Review and Outlook of Ongoing Research

Abstract

A review of the ongoing research on black start (BS) service integrated with offshore wind farms (OWFs) is presented in this paper. The overall goal is to firstly gain a better understanding of the BS capabilities required by modern power systems. Subsequently, the challenges faced by OWFs as novel BS service providers as well as an outlook on the ongoing research which may provide solutions to these are presented. OWFs have the potential to be a fast and environmentally friendly technology to provide BS services for power system restoration and, therefore, to ensure resiliency after blackouts. As a power electronic-based system, OWFs can be equipped with a self-starter in the system in order to perform BS. The self-start unit could be a synchronous generator (SG) or a power electronic unit such as a grid-forming (GFM) converter. Preliminary BS studies performed in PSCAD/EMTDC are presented in a simplified OWF system via an SG as the self-start unit. Consequently, technical challenges during the BS procedure in an OWF benchmark system are outlined via theoretical discussions and simulations results. This is useful to understand the threats to power electronics during BS. Finally, the most relevant GFM strategies in the state-of-the-art literature are presented and their application to OWF BS is discussed.

Innovative Energy Management System for MVDC Networks with Black-Start Capabilities

“…Different network segments may be operated in isolation following large-scale elongated network contingency. Once the issue is alleviated, these segments can be gradually grouped and even used to black-start neighboring areas [32]. In case the investigated MVDC distribution network is required to participate in such black-start scenario upon receiving a request from the utility operator, then it should be ready to energize its AC grid-interfacing assets.…”

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

“…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.…”

“…One solution is to integrate a battery energy storage system (BESS) into the OWF. From that perspective, determining the optimal size of BESS to enable the wind farm to operate as a black start source is necessary from both economic and technical points of view [1], [3], [7].…”

Novel Converter Solutions with a Modular Multilevel Structure for High-Power Medium-Voltage Electrical Machine Drive Applications

“…The MMSC submodule string is built with FB submodules, which are composed of four IGBTs and of one capacitor. The submodule IGBTs must be capable to block the voltage V sub , defined according to (59), and must be capable to conduct the string current (I string ), defined according to (62). Once again, considering the ideal case where V sub = 2V peak N , then the power ratings of the IGBTs of the MMSC's FB submodules can be described as follows:…”

“…Finally, ESSs could keep a wind farm operational during a fault that would isolate the power plant from the grid, absorbing the generated energy and keeping the local grid active. When the fault was cleared, the WT with integrated battery could help to black start the grid if necessary [62]. So, in this Ph.D. thesis, a second novel converter topology is proposed mainly for modern/future high-power medium-voltage WTs.…”