Researchs On The Method Of Transformer Vibration Measuring Based On Velocity Sensor

Power transformer can convert voltage from one level to another level. It is a essential equipment in the power grids. With the rapid development of power grids, the voltage level is increasing as well and the number of power transformer is larger and larger. The reliable operation of the power transformer is closely related with the power grids’ safety and the power quality. Along with smart substations, smart power grids and other electric power construction engineering are put forward and constructed, on-line monitoring of transformer is more and more important.The selection and precision of the measured parameters can affect the performance of the on-line monitoring system directly. In this paper, a transformer vibration measurement method is proposed after analyzing the development status of on-line monitoring system of transformer. The paper designs a series of vibration measurement algorithms which are used to calculate the characteristics of the vibration signals in time domain.This paper mainly focuses on the vibration velocity signal. Firstly, we build the measurement terminal. In this part, the paper emphasizes on the hardware design including the control module, data collecting module, communicating module and storage module, and also on the design and the realization of software framework. Secondly, the paper discusses the related algorithms which include the RMS of signal that is periodic and continuous, digital integral and digital differential. When discuss the RMS of signal, the paper mainly solves two problems. One is at least how many points in each cycle, discrete method can accurately represent valid values. The other is at least how many sampling points, the result will be ideal when the signal cycle is hard to calculate. When design the digital differential algorithm, according to the statistical characteristics of the disturbance signal and minimum variance theory, this paper puts forward a more accurate digital differential algorithm based on FIR filter. When design the digital integral algorithm, this paper mainly discusses how to improve the signal to noise ratio(SNR) of original signal by Wiener filtering and how to remove trend term by the least square method.All algorithms of the paper are not only simulated and compared with other algorithms on the platform of Matlab, but also tested on the embedded platform by using actual vibration signals. The results shows that our algorithms are fast and precise.It can meet the requirement of online monitoring system totally.