Design Of Transformer Winding State Monitoring And Fault Diagnosis System

Power transformer in operation will inevitably suffer all kinds of short-circuit current, which makes the chance of transformer winding damage increase, and threats the normal operation of the transformer. To carry out transformer winding on-line state monitoring and diagnostic work is very necessary, which can realize the purpose that timely diagnosis and treatment of winding fault, and guarantee the stable and reliable operation of the power system.Two kinds of analysis method of transformer winding state on-line monitoring is researched in this paper. Firstly, it analyzes the relationship between transformer short-circuit reactance and winding space structure, and the method that uses short-circuit reactance to diagnose winding state is established as the main analysis method. It establishes the transformer winding short-circuit reactance identification model, and uses the least squares parameter identification method, through the measured value of transformer winding three-phase voltage and current signals to identify and calculate the short-circuit reactance, and according to the relationship between short-circuit reactance and winding deformation, which can realize the state of the transformer winding on-line monitoring; Secondly, in order to make up for the deficiency that short-circuit current method can not identify winding small deformation, when the sudden short circuit happens, transformer winding vibration characteristics are analyzed in theory in this paper. The results show that vibration acceleration and winding structure parameter are closely related, it puts forward the analysis method that monitors transformer winding state based on vibration amplitude and energy distribution. Which can be a good complement of the short-circuit reactance method.Finally, the transformer winding state monitoring and diagnosis system is designed which uses short circuit reactance on-line monitoring method as the main diagnostic methods and uses vibration analysis as auxiliary diagnosis method. The monitoring system uses DSP+STM32as the machine control core, and programs PC monitoring software with VC++language, the data acquisition unit measures transformer winding instantaneous voltage, current signals and vibration signal, realize the functions of transformer winding parameters identification and diagnosis in the PC platform. Stable and reliable hardware circuit design and software design of the rigorous structure can avoid the artificial additional error, and improve the system stability and reliability, which can satisfy transformer on-line monitoring, remote communication and winding state diagnosis requirements. According to the test, the system is running well, and the feasibility of the design is verified.