Wind turbine contribution in frequency drop mitigation - modified operation and estimating released supportive energy

Abstract

Wind energy high penetration levels in power systems require robust and practical operation algorithms to maintain and improve the present conventional systems performance. Thus, several studies consider the impact of wind farms installation on grid frequency, especially during frequency drops. The proposed algorithm makes the wind turbine provide promising support during frequency deviations through two operation modes, namely, normal and support. Normal mode controls wind turbine output by adjusting rotational speed and pitch angle according to the incident wind speed category. Novel normal operation secures wind turbine positive contribution in frequency deviations curtailment regardless of poor accompanying wind speed conditions. The innovative concept of merging pitch de-loading and rotational speed overproduction deceleration is implemented to avoid continuous de-loading; hence wasted wind energy is reduced. Wind turbine generator is overloaded when frequency drop occurs during high wind speed. Major algorithm parameters are tuned based on wind turbine specifications and dominant wind speed conditions at wind turbine location. The amount of supportive excess energy during frequency deviation clearance is estimated at different wind speed circumstances, including serious wind speed drop events. An islanded medium capacity hypothetical benchmark system is implemented to examine the proposed algorithm through MATLAB and Simulink simulation environments. © The Institution of Engineering and Technology 2014.