Guan Jianxin

The condition assessment of transformer bushing based on fuzzy logic

Transformer bushing is an outlet device which leads the internal high-voltage to the outside of transformer. It is not only an important part of power transformer, but also is very important power transmission equipment. The effective condition assessment for transformer bushing, to guide the operation and maintenance of bushing and reduce the failure probability, have an important theoretical and practical significance. This paper focuses on condition assessment of transformer bushing. Aiming at the problem that there are so many assessing factors and indices, which may reflect the different aspects of transformer bushing and have different assessing weights, the decision-making assessment model based on fuzzy logic is proposed in this dissertation. A fuzzy membership function is constructed to describe the factor layer of evaluation model. According to the fuzzy evaluation results, the original basic probability assignment, which is used for decision-making model of evidential reasoning, is determined. Thus the basic probability assignment is obtained by evidence reasoning, and finally the assessment results are determined based on the decision rules of the maximum basic probability assignment function. Some examples show that this method is accurate and reliable.

Test technology of UHV AC bushing and its application

For the urgent needs of the bushing test technology and inspection method with the rapid development of UHV transmission project, based on the technical requirements of the UHV transformer bushing and use for reference on the existing transformer bushing test technology, a complete set of UHV transformer bushing test system including insulation test, thermal rise test has been established, and also the relevant test methods has been proposed. The test technology proposed in this paper has been applied to the UHV transformer bushing used in the UHV power transmission engineering, meanwhile the validity of the test system and technology has been verified.