Lagrange interpolating polynomial–based deloading control scheme for variable speed wind turbines

In this paper, an adaptive deloading scheme is proposed for enhancing the output power from the deloaded variable speed wind turbine generator (VSWTG). The deloading operation of a wind turbine generator (WTG) creates a reserve power margin at its maximum power point operation that can be utilized for stabilizing the frequency deviations of the power system during system contingencies. The output power of the deloaded WTG is regulated dynamically during the system events for improving the primary frequency response. The nonlinear power characteristic curve of the wind turbine is treated with a Lagrange interpolating polynomial (LIP) technique for increasing the output power of the deloaded WTG. Moreover, LIP-based deloading of WTG contributes a better frequency dynamic performance during different power system scenarios such as the fluctuations in wind speed and change in load than the traditional control scheme. Due to the smoothing in frequency response with a faster settling time, the proposed LIP-based deloading scheme can comply with the necessities of the grid codes of the wind-integrated power system. The real-time hardware-in-the-loop (HIL) simulation results are exhibited to validate the proposed deloading methodology in support of the theory. The HIL platform is realized by using the real-time simulator manufactured by OPAL-RT Technologies.