ThePD testerunder Wuhan UHV can help many power workers conduct various power tests more conveniently.
PD Inspection (Partial Discharge Inspection)
Definition:
1. Purpose of PD Inspection
Evaluate insulation integrity.
2.How to conduct PD examination? (Main detection methods)
PD can produce various physical and chemical effects, therefore there are multiple detection methods:
Electrical measurement method:
Pulse current method: the most classic and standardized method. By detecting the pulse current signal generated by PD collected by coupling capacitors or high-frequency current transformers. Capable of measuring key parameters such as discharge capacity, phase, and frequency. Commonly used in laboratories, factories, and offline experiments.
Electromagnetic coupling method:
High frequency current transformer: installed on the equipment grounding wire to detect the RF current signal generated by PD.
Transient ground voltage method: detects the transient voltage induced by PD electromagnetic waves on the metal casing of the equipment. Commonly used for rapid live detection of metal enclosed equipment such as switchgear.
Ultra high frequency method: detects electromagnetic waves in the GHz frequency band generated by PD. Strong anti-interference ability, locatable, suitable for large equipment such as GIS and transformers.
Acoustic measurement method:
Ultrasonic method: Use ultrasonic sensors to detect the sound waves (pressure waves) generated by PD. The biggest advantage is the ability to locate discharge points. Commonly used in transformers GIS、 On site inspection and positioning of cables and other equipment.
Optical measurement method:
Use photomultiplier tubes or ultraviolet imagers to detect the light generated by PD (usually in the visible or ultraviolet wavelength range). The application scenarios are relatively limited (such as transparent media or specific devices).
Chemical method:
Detect chemical products (such as ozone, nitrogen oxides) or dissolved gas analysis generated by PD. More commonly used as an auxiliary tool for gas analysis in transformer oil.
