The State Monitoring On Transformer And Its Application

With the enlarging of grid and improvement of automatic level, tasks in equipment servicing and maintenance are heavier and heavier, the costs are getting higher and higher. Periodic maintenance causes the problems of equipment maintenance too much or too little, huge waste of resources and the insecurity. Online monitoring of transformer can get the real time information of transformer operation, and the augural characters of equipment failures. By the technique of failures diagnosis, possible failures can be judged, and measurement can be taken in advance to prevent the occurrence of major accidents.As online monitoring of the transformer is basically limited to monitoring the value of a single variable at present, there is no general integrated monitoring system by which multiple variables can be monitored. It aims to develop a comprehensive online transformer monitoring system. It can monitor the conditions of oil fault gases in the transformer, insulation status of high voltage bushing, partial discharge of the transformer, DC magnetic bias status of the center, the transformer core clamping pressure and vibration etc.,and synthetically analyze the conditions. Then it makes a overall appraisement to the health status of the transformer.Therefore, this paper aims to carry out research work on how to build a complete transformer condition monitoring system, as follows.1.Integrated application of new technologies are signal sensing, data acquisition, modern digital signal processing and graphical programming etc.On the basis of analysis and processing of the monitoring data, the actual operating state of the transformer can be determined. It is important to prevent hidden failures and to ensure the security, economic and reliable operation of power system.2.Research the analysis of diagnosis on the fault gases in the oil of transformer. A comprehensive diagnosis system based on Borda model is proposed. It is combined the methods of Rogers three-ratio codes, the Japanese electric co-research method, non-coding ratio method, IEC three-ratio method, IEC-60599, David triangle analysis, to avoid one-sidedness of single diagnosis system to reduce the misjudgment probability of system.3.It monitors and diagnoses the HV bushing of transformer at which insulation accident is most likely to happen. Theory and application on online monitoring of the HV bushing is described, to avoid the occurrence of failures. Reliability problem caused by sensor on the connection of the end of screen in the HV bushing is proposed. And test program is given.4.Monitor the influence subject to DC magnetic bias on the Transformers caused by weather conditions of much direct current transmission areas and coastal areas,to avoid the generation of Transformer vibration Fault and the further deterioration of the situation. Monitoring program of transformer core winding vibration is also proposed. It monitors the health status of the core windings of transformer.