Research Of On-line Oil Chromatogram Monitoring And Diagnosis For Transformers Of Nuclear Plant

In the conventional island of nuclear power plant, transformers are the most maintransformation equipments, their running states directly affect the safe operation ofnuclear power plant. According to the document “The Notice About StrengtheningSupervision And Management Of Nuclear Power Plant’s Main Transformer”[National Nuclear Security lette〔r2010〕No.86] which issued by the National NuclearSafety Administration (NNSA), the main transformer of nuclear power plant has beenincluded in the supervisory scope of NNSA. Dissolved gas analysis method has beenconsidered as an effective means of the early fault diagnosis of power transformers.This method which has been widely used can find the latent faults of transformerstimely, and it can promote the transition from regular maintenance to statemaintenance.Dissolve gas analysis on-line monitoring and diagnosis of transformer is looked astransformer’s peripheral equipment, which is applied in nuclear power plant maintransformer need to follow the NNSA requirements. Therefore, this paper combinedthe operation requirements of power plant, researched nuclear power plant maintransformer oil monitoring program, and established a real-time online conditionmonitoring system of main transformer. This system can not only monitor theoperational states of main transformer, but also make fault diagnosis for the warningdata. It can provide decision-making technical reference for maintenance personnel.The thesis mainly discusses from the following aspects:1. Elaborated the research background and meaning, and reviewed the currentresearch situation at home and abroad.2. Combined with the requirements of National Nuclear Security letter〔2010〕No.86, analyzed and discussed the performance requirements for the nuclear powerplant main transformer oil chromatographic monitoring, proposed a solution strategybased on “Distributed Monitoring–Centralized Diagnosis”. This strategy has noeffects to the equipment operation, and we extracted information from stateparameters through the online monitoring of transformer oil chromatography. According to the uniform communication protocol, the information transmittedthrough GPRS to a remote monitoring host which can accommodate a variety ofmonitoring terminals and then analyzed this information intensively. The paper alsogives a specific installation implementation combined with the actual situation.3. To store and analyze date, we established a unified background database. It canrealize the monitoring data resource sharing, deal with the dates flexibly by callingthe resources from the database. Also, it can accomplish the chart analysis, data queryand fault diagnosis.4. Use transformer online gas chromatographic analysis data, combined with theresidual analysis and support vector machine (SVM) method, we madecomprehensive diagnosis for transformer historical data and operation parameters.And finally, we established a fault diagnosis model which was characterized by theDGA, we use this model to make system analysis and fault diagnosis.Finally, the field operation experience and diagnosis result proved that the nuclearpower plant main transformer oil chromatographic online monitoring and diagnosticprograms which was proposed in this paper reflects obvious advantages in manyrespects, it has a good application prospect.