Passive Filter Tuning for Harmonic Resonance Mitigation in Wind Parks

Harmonic resonances are an important concern in wind parks as they can lead to fines due to violations of regulatory harmonic distortion limits at the point of common coupling (PCC) with the grid, unwanted outages, and potential damage to wind park and grid components. Based on the resonance-free capacitor concept, this paper proposes a method to tune a passive filter to mitigate these resonances while providing the reactive power compensation required by the park at fundamental frequency. This tuning method is applied to a C-type filter topology and the robustness, performance and cost of the resulting filter are assessed to demonstrate its effectiveness and economic viability. A key result is that, when compared to existing methods to tune general purpose filters, which target local harmonic mitigation, the proposed strategy leads to filters with better performance and lower cost as it was tailored for the wind park application, where harmonic voltages must be minimized at a remote location (the PCC with the grid). This is achieved by properly accounting for the effect of the grid and wind park components.