Partial Discharge Tester, abbreviated as PD Tester, is the "stethoscope" for insulation diagnosis of high-voltage electrical equipment.



It is mainly used to detect whether partial discharge phenomena exist inside equipment such as transformers, GIS (Gas Insulated Switchgear), cables, and switchgear cabinets.

Partial discharge is an early sign of insulation deterioration. If not detected in time, it will eventually lead to insulation breakdown and cause major accidents.

According to application scenarios and technical principles, current partial discharge testers are mainly divided into two categories: portable inspection instruments and laboratory/online monitoring systems.

⚙️ Core Detection Principles and Technologies

When partial discharge occurs, various signals such as electromagnetic waves, acoustic waves, light, heat, and chemical reactions are generated. The tester determines insulation status by capturing these signals. The current mainstream detection technologies are shown in the table below:

Table

Detection Technology    Abbreviation    Principle Description    Applicable Scenarios    Advantages

Pulse Current Method    IEC 60270    Captures the pulse current generated by discharge through a coupling capacitor.    Laboratory, factory testing, cable testing    International standard method, accurate quantification, high sensitivity.

Ultra-High Frequency Method    UHF    Receives electromagnetic wave signals in the 300MHz~3GHz frequency band.    GIS, transformers, high-voltage cables    Strong anti-interference capability, high positioning accuracy, suitable for online monitoring.

Acoustic Emission Method    AE    Captures mechanical vibration (acoustic wave) signals generated by discharge.    GIS, transformers, switchgear cabinets    Immune to electromagnetic interference, allows non-contact detection (attached to equipment enclosure).

Transient Earth Voltage    TEV    Detects transient voltages induced on the surface of metal cabinets due to internal discharge.    Switchgear cabinets, ring main units    Extremely simple operation, no power outage required, handheld detection possible.