CHB STATCOM Utilization for Smoothing Power Oscillations of Fixed Speed Wind Farms

Abstract— Electrical output power fluctuations of wind farms inject poor quality of power into the grid. This problem is more remarkable for the wind farms utilizing fixed speed wind turbine generators (WTGs). In this paper the output power of a ۱۰MW wind farm with ۲۴ fixed speed WTGs, is investigated. The most appropriate location for power smoothing based on the short-term power recording and effective power oscillation frequency is determined. A transformerless cascaded H-bridge STATCOM (CHB STATCOM) combined with a mechanically switched capacitor (MSC) is proposed to compensate variable reactive power of the wind farm, as well as to smooth the short-term active power fluctuations. The active power flattening is accomplished by proper sizing of the CHB dc link capacitors according to necessary energy exchange. By comparing several distributed and centralized schemes, a ۲MVar CHB STATCOM, which is economically justified, is proposed. The STATCOM performance for improving power quality of the wind farm is investigated by applying several power profiles acquired from the wind farm using simulink MATLAB environment.

Keywords:

key words—CHB STATCOM , Wind farm , fixed speed WTG , Power Quality , short-term power fluctuation smoothing