Insulation Condition Assessment of Power Transformer Bushing Based on Cloud Model and Kernel Vector Space Model
Zheng Bolin · Gao dianya jishu · 2013
In order to reduce uncertain factors affecting insulation condition assessment of power transformer bushing,we proposed a novel condition assessment method.The randomness and fuzziness of evaluation index classification boundary are fully considered in the method.This combined weighing method includes the objective weight and the subjective weight decided by cloud model and unascertained theory,respectively.A kernel vector space model is established,and the kernel function is used to map the input data into the high-dimensional feature space,in which the index-directed line segment of data sample and ideal directed line segment of insulation grade standard sample are defined.By calculating the weighted cosine value between directed line segment in each data sample and ideal directed line segment in grade standard sample,the approaching degree is obtained.By using the approaching degree,the insulation condition assessment is transformed into the pattern recognition in vector space,from which the insulation condition grade is obtained.An actual example shows that,in the first test of a bushing,its insulation condition is close to the normal state in the largest degree,meaning that it is in normal state;yet in the second and third tests,it is close to the fault state in the largest degree,meaning that it is in fault state.