GHJFD Partial Discharge Detector



The GHJFD Partial Discharge Detector provides a fast and simple method for non-invasive partial discharge detection, used to identify potential insulation faults that may cause power outages or personal injury. Partial discharge is an electrical discharge that does not completely short-circuit the electrodes. The amplitude of such discharges is usually very small. However, they do cause continuous degradation of the insulation layer, ultimately leading to failure of electrical equipment.



 



Partial discharge radiates energy in the following ways:



Electromagnetic energy: radio waves, light, heat; Acoustic energy: sound waves, ultrasonic waves



Gases: ozone, nitrogen oxides.



The most practical techniques for non-invasive detection are based on detecting the high-frequency part of the electromagnetic spectrum and ultrasonic signals. This product is a specially developed, easy-to-operate instrument for detecting electromagnetic wave and ultrasonic activity.



 



Airborne ultrasonic discharge activity



Acoustic radiation from partial discharge activity occurs across the entire acoustic spectrum. It is possible to hear sounds, but it depends on the individual's hearing ability.



Using an instrument to detect the ultrasonic part of the acoustic spectrum has several advantages. Instruments are more sensitive than the human ear, independent of the operator, operate at frequencies above audio, and have stronger directionality.



The most sensitive detection method is to use an ultrasonic sensor with a center frequency of 40 to 200 kHz. This method can very successfully detect partial discharge activity.



 



Airborne electromagnetic discharge activity



When partial discharge activity occurs in the insulation of high-voltage switchgear, it generates high-frequency electromagnetic waves that can only leak from the switchgear to the external surface through openings in the metal enclosure. These openings can be enclosure gaps or gaps around gaskets and other insulating components.



When electromagnetic waves propagate outside the switchgear, they induce transient voltages on the grounded metal enclosure. Transient Earth Voltages (TEV) range from a few millivolts to a few volts, have a short duration, and have rise times of a few nanoseconds.



Partial discharge activity can be detected non-invasively by placing the probe on the outside of the switchgear.