Operational reliability assessment considering independency between wind power ramps and frequency sensitive loads

With the increasing wind power penetration, power system frequency is more vulnerable especially when gust wind periods. Frequency control is used to restore system frequency back to the rated value. But, during frequency control processes, demand of frequency sensitive load (FSL) is different from that of frequency-insensitive load and changes with the change in system frequency. It is necessary to consider load demand combined with dynamic frequency deviation. This paper proposed a new reliability evaluation method of generation systems based on blade-element theory and frequency control method. The blade-element theory is utilized to improve the evaluation accuracy of wind power output in the presence of wind power ramp events (WPREs). The frequency control considering dynamic demand of FSL is used to mimic frequency regulation processes and establish reliability evaluation model. Case studies are presented using wind data from a wind farm in Shanxi Providence, and the results suggest that reliability problems caused by FSL can’t be ignored in some cases.