Judgment basis for partial discharge tester to detect defects

1. Judgment basis for defective parts

(1) Multi-sensor positioning

Use time delay method to achieve spatial positioning. Use multiple sensors to measure the suspected fault at the same time, and use the sensor that the signal arrives first as the trigger signal source to obtain the propagation time of the ultrasonic wave from the discharge source to each sensor, and then according to the ultrasonic propagation speed and direction in the equipment medium, You can determine the spatial location of the discharge source.

(2) Single sensor positioning

Move the sensor, test different parts of the air chamber, find the big point of the signal, and the corresponding position is the defect point. Two methods are used to determine whether the defect is on the tank or the center conductor.

Method 1, by adjusting the measurement frequency band, reduce the measurement frequency of the band-pass filter from 100kHz to 50kHz. If the signal amplitude is significantly reduced, the defect location should be on the shell; the signal level is basically unchanged, the defect location Should be on the center conductor.

Method 2: If the large value of the signal level occurs in a large range of the circumference of the tank surface, the defect location should be on the center conductor; if the large value occurs at a specific point, the defect location should be on the shell. Defect type judgment basis.