Can an Acoustic Camera Detect Partial Discharge? What Engineers Need to Know

Partial discharge (PD) generates ultrasonic energy across a broad frequency range — typically 20–300 kHz — as electrical sparks and corona activity create rapid pressure waves in the surrounding air or insulating medium. Acoustic cameras with sensitive microphone arrays are inherently capable of detecting these ultrasonic emissions and localizing them to specific equipment components.

The GSW Series acoustic camera from Unitech Tools, with its 136-microphone array and wide frequency response, can detect PD activity in switchgear, transformers, and cable terminations — even in noisy substation environments.

Unlike TEV (Transient Earth Voltage) sensors that must be placed on the equipment surface, acoustic cameras can detect PD from a distance, making them ideal for rapid substation surveys and inaccessible equipment.

The SC Series PD Detector combines TEV, ultrasonic (contact), and high-frequency current transformer (HFCT) methods for comprehensive PD analysis. When used together with an acoustic camera for initial screening, you get a complete PD detection workflow.

An efficient PD detection strategy uses both technologies:

1. Initial screening using the GSW acoustic camera — walk through the substation and scan each switchgear panel, transformer, and cable termination from a safe distance
2. Identify PD signatures — acoustic camera shows the approximate location of PD activity as a colored hotspot on the visual image
3. Confirm and measure using the SC Series PD Detector — place TEV sensors on the identified panels to measure PD magnitude (pC) and repetition rate
4. Classify PD type — using the SC Series pattern recognition to distinguish between corona, surface discharge, and internal voids
5. Document — capture both acoustic images and TEV measurement data in a combined report

Browse the acoustic camera and PD detector ranges from Unitech Tools for comprehensive substation inspection solutions.