Comparative study of the impact on subsynchronous resonance characteristics from the different location of wind generators in a large wind farm

In addressing the subsynchronous resonance (SSR) issue associated with series-compensated wind farms, most of the literatures use a single wind turbine generator (WTG) to represent the entire wind farm, without considering the impact on SSR characteristics from the wind speed, output power of WTGs at different locations and the parameters of cables connecting those WTGs. This paper divided the entire wind farm into two sub wind farms and used an aggregated DFIG to represent each sub wind farm. The small-signal model of the series-compensated two-WTG system was built and then the SSR characteristics under different wind speed, output power and cable impedance were investigated. It is found that the location of WTGS has great influence on SSR characteristics when the wind speed is fixed. The WTGs near the collecting bus have relatively greater impact than those far from the collecting bus. If the generation produced by the whole wind farm is fixed, the higher percentage the far-end WTGs account for, the more stable the system becomes. Generally, when the impedance of the line connecting the WTGs and the collecting bus is increased, the stability of SSR will be improved. © 2015 Chinese Society for Electrical Engineering.