电路引用Acoustic energy shifting in transformer oil at different temperatures.pdfVIP

2356 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 20, NO. 3, JULY 2005 Power Engineering Letters____________________________________________________ Acoustic Energy Shifting in Transformer Oil at Different Temperatures Xiaodong Wang, Baoqing Li, Zhixiong Xiao, Onofrio L. Russo, Harry T. Roman, Ken Chin, and Kenneth R. Farmer Abstract— In this letter, partial discharge (PD) acoustic waves for different temperatures have been detected using a piezoelec- tric acoustic sensor. The experiments results are analyzed using the Fast Fourier Transform (FFT). Calculations are shown to agree with the experimental results. This acoustic energy (AE) analysis appears to be an effective method to monitor the temperature of the transformer oil. Index Terms—Energy shifting, partial discharge (PD), tempera- ture. I. INTRODUCTION HE CONSIDERABLE studies have been conducted Fig. 1. Partial discharge in transformer oil. Tin partial-discharge (PD) acoustic signal detection for oil-immersed transformers [1]–[6]. The importance of tempera- ture of transformer oil has not been previously investigated yet. This letter which presents experimental and theoretical results, shows an acoustic energy shift from low to high frequencies with increasing temperature of the oil (from 25 to 40 ). II. EXPERIMENT SETUP A piezoelectric sensor is immersed in the transformer oil to detect PD sounds which are sent to a digital oscilloscope for real time display and storage. Then the data is sent to a computer for fast Fourier transform (FFT) analysis. The PD generation tank consists of an oil-filled plastic tub, two micromanipulators for placing and holding opposing electrodes in close proximity, and two hypodermic needles to serve as sha