Design Of On Line Monitoring System For Transformer Inter Turn Short Circuit Fault

With the economy and technology of the continuous vigorous development,people's living level is gradually rising.As a result,the electricity demands growth.The power is closely related to human life and production and the power system safety and reliable operation is directly related to social stability and healthy development.The reliability of power system operation is affected by many factors.Power transformer is the heart of the power system,playing an irreplaceable role in electrical energy transmission process,its stable operation is almost directly related to the reliability of the power system.According to the domestic and foreign operating experience and statistical data,transformer winding damage of transformer accounts for 60%-70%of the total failure of all transformers and transformer winding insulation defects or external cause failure is the main direct cause of the problem,in view of this,research on transformer winding inter turn short-circuit and analysis of the mechanism,influencing factors and development preventive measures related to the work need to be started.On the basis of theoretical research,then further develop transformer winding interturn short circuit monitoring device.Through such device the slight interturn short circuit fault will be accurate early warning,and then real-time fault information is uploaded to the backstage dispatching center,operation and maintenance personnel then take correspongding preventive measures according to the fault diagnosis results,which can help to prevent transformer fault caused by unnecessary economic losses.At present there are many transformer short circuit monitoring method,each method has its characteristics,and achieved certain effect on certain occasions.Common methods such as leakage inductance,voltage and current ratio method of dissolved gas analysis,online monitoring method as from the economy,effectiveness and real-time comprehensive consideration.In general,online monitoring is a kind of development trend.At first,this paper summarizes the domestic and foreign relevant transformer interturn short circuit current situation of monitoring,and describes the principle of all kinds of test methods and their advantages and disadvantages.At last,we decide to use power loss method.First analyzed the current and voltage characteristics and transformer power loss changes before and after interturn short circuit happened,It is proved out that interturn short circuit will bring additional power loss,and the power loss increases when interturn short circuit develops,besides,power loss of fault phase is much higher than non-fault phase.Transformer interturn short circuit monitoring device is developed by using the principle.It can monitor the voltage and current on every side of the transformer and calculate the power losse,then delivery the messages to the control system of electric power company through GPRS network.The software system then analyze informatio received with the method of fuzzy and expert system and so on.What's more,the system will decide whether or not the interturn short circuit fault happens and which level,like slight,very slight,and fearful,the fault is.The system will send a message to workers related and raise the alarm.