Study On Transformer Insulation Condition Assessment Based On Cloud Matter Element Theory

Transformer is an essential junction component in power system. Its reliability is closely related to the security and stability of power system. The important element for transformer’s economic and reliable operation is carrying out condition-based maintenance and strengthening the life-cycle management. The key to success about condition-based maintenance is making an accurate condition assessment of transformers. Currently, the assessment of transformer domestic and foreign mainly focus in consolidated operating state, but very few specific studies on assessment about insulation state. Therefore, this paper proposed a method to assess transformer insulation condition based on cloud matter element theory.The insulation of transformer in this paper is firstly divided into three parts namely insulating oil, pipe insulation and solid insulation based on the composition of transformer insulation. On the requirement of assessment and the actual operability, a layered evaluation system about transformer insulation condition is built. Secondly, the subjective weight of each indicator and project can calculate by improved AHP based on cloud model, and the entropy method is applied to get the objective weight of each indicator relating to the actual data’s change rate at the same time. Finally, the cloud model instead of the traditional range is used to dividing the insulating state level of transformer. After determine the matter-element of evaluation system, each characteristic element value is regarded as a cloud droplet which is used to calculate the membership degree for each grade cloud. Combined with the weight of each index, the matter element membership degree belong to each condition level can be gained.The examples show that, the insulation condition assessment model for transformer can synthesize multiple attributes and have a reasonable evaluation of each insulation part and the whole transformer.