Provision of power system frequency response in the context of high wind penetration

Models have been developed to assess the extent that wind plant can contribute to power system frequency control and stability. These are important in the context of increasing wind penetration level into power systems and because variable speed wind turbines that are now the dominant technology do not directly contribute to system inertia, but displace conventional generation plant, thus reducing the total system inertia. It is now considered likely that wind generation will have to participate in power system frequency regulation but prior to this work, little was known about the aggregate impact of extensive wind capacity in this regard, although there has been extensive prior research on the modification of individual turbine controllers to deliver inertial response in the event of rapidly falling system frequency, and droop response so as to contribute to continuous frequency service. A novel probabilistic approach has been developed to assess how the aggregate synthetic inertial response from wind plant at a given time depends on the available wind. The calculation of collective synthetic inertial response is based on an approach to modelling wind turbulence where wind variations over a short period of time (10 seconds in this modelling) are assumed to be adequately described by a Gaussian probability distribution with a set mean wind speed and variance determined by the site turbulence intensity. This approach is then further expanded to assess the aggregate inertial response available from wind generation across the GB power system and by using a simplified lumped representation of the rest of the power system, allows the interaction between the wind plant, through its controllers, and the power system to be represented. The complete model provides a way to evaluate synthetic inertial response from wind generation under time varying wind speeds on an hourly basis and across the regions, and also as a result of turbulence and short term wind speed variation across wind farms. This research has also shown that the power output of wind turbines can also be actively controlled to provide droop response and to participate in primary frequency response. Different approaches to delivering droop response from wind plant have been investigated. The combination of droop and inertial response has been assessed for a significant frequency event and the results show that the combined approach can provide an improved performance than either droop or inertial response alone.Models have been developed to assess the extent that wind plant can contribute to power system frequency control and stability. These are important in the context of increasing wind penetration level into power systems and because variable speed wind turbines that are now the dominant technology do not directly contribute to system inertia, but displace conventional generation plant, thus reducing the total system inertia. It is now considered likely that wind generation will have to participate in power system frequency regulation but prior to this work, little was known about the aggregate impact of extensive wind capacity in this regard, although there has been extensive prior research on the modification of individual turbine controllers to deliver inertial response in the event of rapidly falling system frequency, and droop response so as to contribute to continuous frequency service. A novel probabilistic approach has been developed to assess how the aggregate synthetic inertial response from wind plant at a given time depends on the available wind. The calculation of collective synthetic inertial response is based on an approach to modelling wind turbulence where wind variations over a short period of time (10 seconds in this modelling) are assumed to be adequately described by a Gaussian probability distribution with a set mean wind speed and variance determined by the site turbulence intensity. This approach is then further expanded to assess the aggregate inertial response available from wind generation across the GB power system and by using a simplified lumped representation of the rest of the power system, allows the interaction between the wind plant, through its controllers, and the power system to be represented. The complete model provides a way to evaluate synthetic inertial response from wind generation under time varying wind speeds on an hourly basis and across the regions, and also as a result of turbulence and short term wind speed variation across wind farms. This research has also shown that the power output of wind turbines can also be actively controlled to provide droop response and to participate in primary frequency response. Different approaches to delivering droop response from wind plant have been investigated. The combination of droop and inertial response has been assessed for a significant frequency event and the results show that the combined approach can provide an improved performance than either droop or inertial response alone