The invention discloses a power distribution network sag frequency
estimation method based on an optimized K-nearest neighbor method and process
immunity, which is characterized in that an optimal K-nearest neighbor parameter is searched based on a ten-fold
cross validation method, and accurate distribution characteristics can be obtained for a line with relatively complex fault distribution; the defects that a traditional method is insufficient in approximation capability, too complex in model, poor in anti-interference capability and the like are overcome, and therefore a more objective and real
voltage sag frequency
estimation result is obtained. Based on the protection cooperation condition of a feeder
automation system of a power distribution network, the
voltage sag mode suffered by a user is analyzed and summarized, and for the defect that the influence of an existing method on
voltage sag + short-time voltage interruption and continuous
voltage sag is not considered sufficiently, a user process parameter change equation before and after aggregation is established and solved, so that the user sag mode is obtained. According to the method, the problems of under-
estimation and over-estimation of the sag in the traditional method are avoided, and meanwhile, the defect that short-time interruption is not brought into statistics in the prior art is overcome.