EnerNex designed a 34.5 kV C-Type filter for the 60 MW Mountain Wind Plant located in Fort Bridger, WY. The primary objective of the filter design was to avoid a potentially high fifth harmonic resonance. Shunt capacitors inside the wind farm formed a fifth harmonic local resonance which could increase harmonic voltage and current distortion levels to unacceptable levels. The C-Type filter was designed to shift resonances away from offending harmonics while providing adequate harmonic attenuation, power factor correction and voltage support.