Electrical Quantity And Dissolved Gas-in-oil Quantity Combined Status Monitoring And Health Diagnosing Of Power Transformers

As the core equipment of electrical power system, power transformers not only play a very important role in voltage transformation, electrical energy distribution and transmission, but provide essential power service as well. The normal operation of the power transformer is the guarantee for the safety, reliability, high-quality and economic operation of power system. The status monitoring and health diagnosing of power transformer can help to find its abnormal or faulty status and to prevent the escalation to bigger or even collapsing status. So this paper takes on this topic.First, this paper studies transformer fault diagnosability. Through this study the aimlessness of fault diagnose can be avoided. In this paper two methods to study the transformer diagnosability are presented, one is based in information entropy, the other is based in fault matrix.Transformer status monitoring and health diagnosing based on electric quantity is another important aspect of this paper. The loss will increase when the transformer incurs faults and abnormalites, and both theory and test results prove that the symptoms will be more obvious with the increase of the load . The system base on this response has the advantages of quick response and local fault positioning.The parallel system based on dissolved gas-in-oil quantity is IEC three ratio method, because IEC three ratio method have drawbacks such as no matching, incomplete codes, and inability to diagnose multiple faults .So this paper put forward two mathematical DGA methods: fuzzy three ratio method and extension set method. Simulation proves that these two methods can overcome these drawbacks, thus greatly enhanced diagnosing accuracy.The system of transformer status monitor and health diagnose based on the fusion of information such as electrical quantity, dissolved gas-in-oil analysis, vibration and noise signals. In this paper decision fusion is used as it has the characteristics of high flexibility, high fault tolerance, strong ability against interference, and low dependence for signal sensor. For the actual installation is not realized, this paper mainly studies the mechanism of the proposed system.