Pillar 4 of 8 · SDT Ultrasound Solutions methodology
Ultrasonic Detection of Corona Discharge and Electrical Arcing
Ultrasonic electrical fault detection is aimed at identifying corona discharge, electrical arcing, and insulation defects on electrical equipment. These discharges produce very little heat, so thermal cameras often miss them, while ultrasound hears them. The check runs on live equipment from a safe distance and works well alongside thermography.
Corona discharge, arcing, and insulation defects generate ultrasonic waves picked up by airborne sensors. A parabolic reflector lets you listen to discharges from a safe distance — on switchyard insulators, overhead line couplings, and transformer bushings.
KEG TRK supplies SDT Ultrasound Solutions detectors for electrical diagnostics across Almaty, Astana, Atyrau, Aktobe, and the whole of Kazakhstan. Training in the ultrasonic electrical diagnostics methodology is included with every delivery.
Types of Electrical Faults Detected by Ultrasound
One instrument — full control of a plant's electrical equipment.
Corona Discharge on Insulators and Cables
Corona discharge occurs on insulation surfaces under local overvoltage. It gradually degrades insulation and can lead to breakdown. Ultrasound detects corona from a safe distance — with no contact with the equipment.
Electrical Arcing and Tracking
Arc discharges between conductors generate a strong ultrasonic signal. The detector instantly responds to arcing defects in switchgear, transformers, and cable connections.
Connection Point Defects
A loose or oxidized contact that has started to arc gives a characteristic crackle. Ultrasound picks it up through cabinet grilles and gaps without opening the door; heating at such contacts is best confirmed with a thermal camera.
Substation and Overhead Line Insulators
Contaminated and damaged insulators on open switchyards and overhead lines create surface discharges. Ultrasonic scanning from a safe distance without approaching live parts.
How to Perform Ultrasonic Electrical Fault Diagnostics
Three steps from scanning to trend monitoring.
Point the Sensor at the Equipment
Use an airborne sensor with a parabolic reflector (for substations, switchyards) or a flexible waveguide (for cabinets). Scan from a safe distance — no need to open cabinets.
Listen To and Measure the Signal
Corona discharge creates a characteristic "hissing" sound when heterodyned, while arcing produces "crackling." The instrument displays the level in dBµV for objective assessment and comparison.
Log the Data and Track the Trend
Save the measurement, audio recording, and point coordinates. With regular measurements, the instrument builds trends — a rising signal indicates defect progression and replacement timing.
Benefits of Ultrasonic Electrical Fault Diagnostics
Safety, early detection, and documentation for power utilities and plants across Kazakhstan.
Safe Inspection Under Voltage
Ultrasonic diagnostics are performed remotely — without contact with live parts. There is no need to de-energize equipment to carry out the inspection.
Early Detection Months Before Failure
Corona discharge develops gradually. Ultrasonic monitoring identifies emerging defects months before insulation breakdown and an emergency shutdown.
Diagnostics in Noisy Environments
The detector listens to a narrow band around 38 kHz, where there is far less industrial noise than in the audible range. Corona and arcing are detected amid the noise of running transformers, motors, and ventilation equipment.
Reduced Fire and Explosion Risk
Electrical arcing and insulation defects are a leading cause of electrical fires. Timely detection prevents catastrophic consequences.
Documentation and Trending
Modern detectors record the signal and allow tracking defect progression over time. A rising amplitude is a signal for unscheduled maintenance.
Revealing Invisible Defects
A thermal camera only shows overheating. Ultrasound detects active discharges at their earliest stage — before the temperature has risen to the thermal camera's threshold.
Want to Detect Hidden Electrical Equipment Defects?
KEG TRK specialists will select the optimal kit for your voltage class and equipment type.
Get a ConsultationInstruments for Electrical Fault Diagnostics
From the entry-level ULTRAChecker to the professional SDT340 with parabolic reflector.
SDT340
ProfessionalA multi-sensor platform with Bluetooth HD, an airborne sensor, and a parabolic reflector for remote diagnostics.
Suited for: Critical high-voltage equipment
SDT270
Data and TrendsA data collector with signal recording and trends in Ultranalysis Suite 3 for tracking defect progression.
Suited for: Electrical equipment monitoring program
ULTRAChecker
Easy StartA specialized detector for basic electrical fault diagnostics with no training required.
Suited for: First step, basic inspection
SDT200
For BeginnersA basic detector with an immediate audible indicator to start an electrical diagnostics program.
Suited for: Onboarding a monitoring program
Explore the Other Pillars of Ultrasonic Testing
The SDT methodology covers 8 areas — one instrument solves every task.
Frequently Asked Questions About Ultrasonic Electrical Fault Diagnostics
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