Abstract: Voltage sag control is non-standardized. Due to the lack of user-side details, it is hard to estimate the control capacity, which frequently causes excessive or inadequate sag controls. Considering the fact that the control object is affected by the multidimensional characteristics of voltage sags, we carry out a study on the problem of tolerance ability and control capacity identification of the control objects, and propose a Hausdorff distance identification method for sensitive equipment tolerance ability with consideration of the their sag multidimensional characteristics. By introducing the concept of pattern library, the fuzzy membership is used to judge the voltage tolerance ability of control objects. On this basis, an improved voltage sag severity index is put forward, and a control capacity identification method is proposed based on the improved sag severity index and control object capacity ratio. And then the required control cost is estimated. Based on the actual monitoring data of a city power grid, a case study shows that the proposed method is effective and reasonable, and is easy for practical application.

Key words: voltage sag control, sag multi-characteristic, Hausdorff distance, fuzzy membership, control capacity, control cost estimation