Research Of Power Transformer Condition-based Maintenance System Using Vibration Signal Analysis Technology

Electric power, as a form of energy, plays an important role in the industrial development of the country. The power transformer is the important equipment in power system, and power transformer on-line monitoring and fault diagnosis have great significance of safe and stable operation of power system. Conventional power transformer on-line monitoring method gradually exposed some shortcomings in people’s practical application, while maintenance method based on vibration signal analysis technology has shown its advantages, such as analysing the actual operating conditions without stopping the machine, possessing portable devices and operating conveniently. If combined with traditional methods, it can improve the security and economy of equipment operation, meeting the needs of the times and the trend of the times.This paper started from the principle of vibration of power transformer, then discussed the vibration characteristics of the two parts of the iron core and the windings. And then, the vibration signal of power transformer main features is analysed, which is under the influence of cooling system, load parameters and insulation oil temperature. The core and winding deformation and some other faults may be the result of the transformer body vibration, or react in vibration rules.This paper put forward a method to monitor the running state of power transformer by analyzing the characteristics of time domain, frequency domain and time frequency domain. In the characteristic signal calculation, according to the characteristics of vibration signal of power transformer, wavelet decomposition method and the empirical mode decomposition method are chose. They are adaptive extractions in different frequency vibration characteristics by joint time-frequency analysis to obtain more meaningful feature information.Using the feature analysis method, this paper designed a set of state maintenance system based on vibration signal analysis technology. The system is composed of equipment and signal analysis computer to collect vibration acceleration signal.