Partial Discharge Ultrasonic Detection Method and Frequency Characteristics at Oil-filled Cable Terminal

Abstract

In order to effectively detect latent insulation faults at oil-filled cable terminals， the finite element analysis method of acoustic field is used to study the characteristics of partial discharge acoustic field distribution at oil-filled cable terminals， and the method of using fiber optic F-P （Fabry-Perot） sensors to detect partial discharge of terminal liquid-solid composite insulation is proposed. The method uses a typical electrode model to simulate the partial discharge fault of liquid-solid composite insulation， employs F-P sensors with different intrinsic frequencies and piezoelectric ceramic sensors to jointly detect the partial discharge acoustic signal， and analyzes the frequency distribution characteristics of the partial discharge acoustic emission of liquid-solid composite medium. The results show that： the partial discharge acoustic wave of the insulation inside the oil-filled cable terminal can propagate along the high modulus solid and form a strong acoustic field area which is favorable to the detection of the fiber optic F-P sensor； the typical liquid-solid insulation partial discharge ultrasonic wave frequency is rich in the range of 40~180 kHz. Clarifying the distribution range and frequency characteristics of partial discharge sound field in oil-filled cable terminals can effectively improve the sensitivity of partial discharge detection and increase the success rate of partial discharge detection.

Keywords

• partial discharge detection
• acoustic measurement method
• partial discharge acoustic frequency
• cable terminal