A field testing of ancillary services for grid restoration with wind power plants

Abstract:
In the course of the energy transition, the share of decentralized power feed-in in the grid of renewable energy (RE) from volatile source is increasing rapidly. Renewable power sources are already in use during normal grid operation, but not yet during critical grid situations, such as frequency events, or restoration scenarios after a black start. Although wind power plants (WPPs) usually do not serve as black start units, they can provide valuable grid supporting ancillary services, which are currently mainly provided by conventional power plants and controllable loads. Ancillary services from WPPs are only rarely employed, e.g. by limiting the feed-in or for voltage containment in high and extra-high voltage grids. In order to include WPPs in grid restoration and other critical grid situations a dedicated operating mode (“incident mode”) was developed. This incident mode enables the grid operator to fully exploit the technical capabilities of a WPP. We provide evidence that the incident mode allows WPPs to react to frequency events and provide a frequency containment reserve (FCR). The incident mode can be activated both manually from the operation control centre (OCC) and automatically when the communication with the OCC is interrupted. We present the results of a field testing in a WPP with an installed power of 51.9 MW and 22 turbines. The test cases consist of over- and underfrequency events, as well as communication interruption and two blackout scenarios, in which the respective substation is disconnected from the grid.