Preventing wind turbine overspeed in highly turbulent wind events using disturbance accommodating control and light detection and ranging

Abstract

Light detection and ranging (LIDAR) systems can be used to provide wind inflow information to a wind turbine controller before the wind reaches the turbine. Both fatigue and extreme load reduction are possible as a result; in this research, we propose a LIDAR-based controller designed to prevent emergency shutdowns caused by rotor overspeed. This switching controller consists of a disturbance accommodating control (DAC)-based baseline controller and a different DAC linearized about a reduced generator speed for extreme events, also referred to as an extreme event controller. Switching between the controllers was performed using linear interpolation over various transition times, depending on how early the extreme event could be detected. If a gust of wind is detected using LIDAR measurements evaluated by a one-sided cumulative summation algorithm, a relatively long transition time can be used. Switching can also be based on a large output estimation error, y , in which case the transition time is shorter. Once the extreme event passed, control is switched from the extreme event controller back to the baseline DAC. This switching controller resulted in fewer overspeeds when compared with the modified baseline controller, which is a gain scheduled DAC. By preventing overspeeds, the switching controller increased the mean power the wind turbine generated over a simulated 10 min period.

Wind turbine overspeed protection based on polytopic robustly invariant sets

“…x. Unlike some of the reported approaches, 8,21 wind preview is not considered in this study. The difference from the other similar control structures proposed in the literature 22,23 is its exclusively safety feature.…”

“…Approach of Kanev and Engelen was pursued by Pace et al who incorporated light detection and ranging (LIDAR) sensor to perform the CUMSUM test for a wind gust detection. 8 Moreover, they pointed out significance of the turbine rotational speed estimation error for the protection algorithm. It was accounted with a pre-defined threshold that they used as an additional condition for the extreme event trigger.…”

Study of Tower Clearance Safety Protection during Extreme Gust Based on Wind Turbine Monitoring Data

“…However, the wind speed measured in the nacelle is not suitable for control since the nacelle measurement is highly disturbed by the blades. In addition, extreme gusts can be accurately calculated by light detection and ranging (LIDAR) wind measurements [14][15][16][17][18]. However, wind speed varies with the site; thus, each wind turbine needs to be measured individually, and the extensive use of LIDAR will increase costs.…”

Wind Predictions Upstream Wind Turbines from a LiDAR Database

“…The joint control of blades pitch, as well as the individual control of each blade pitch [14], have demonstrated the reduction of extreme loads, the reduction of emergency shutdowns, and the reduction of fatigue loads in wind turbines. The use of nacelle mounted LiDAR measurements of wind speed suggested by Mikkelsen et al [4] allows for the use of feed-forward control algorithms [15,16]. These control systems have been tested with real data [17,18], demonstrating a 10-30% reduction of structural loads.…”