The UL101 ultrasound detector helps locate partial discharge including arcing, tracking, and corona...even when the panels are closed.

Power Transmission and Distribution

The UL101 and PowerBeam are used together to inspect medium and high voltage power lines, switchgear, and transformers. Inspection focuses the detection of corona, which is a symptom of two types of failures including material degradation and indeterminant by other technologies. The UL101 Corona Kit is very affordable and very effective in all types of environments for these tasks. 

"India's Certified R&D Institute has certified the functional aspects of CTRL UL101 with the PowerBeam 300 for detection of corona discharge from 400 kV single suspension insulator string consisting of 1 x 25 Nos. of 120 kN B/s discs with arcing horn and corona control ring and 245 kV single suspension insulator string consisting of 1 x 14 Nos. of 120 kN B/s discs with arcing horn and corona control ring. Readings were taken by the UL101 and PowerBeam 300 from 50, 100, and 150 feet respectively."

How to inspect transmission lines

  1. Scan the Electrical transmission system network such as Insulator or cable string with the CTRL UL101 and PowerBeam300 attachment.
  2. The UL101 will pick up the ultrasound signal which is generated at the source due to Electrical arcing, tracking, or corona discharge.
  3. If there is a continuous corona effect during transmission near the insulator, it results in transmission losses.
  4. The intensity of the ultrasound will increase as you direct the PowerBeam300 scan the area, allowing you to pinpoint which insulator is punctured or damaged.
  5. In most of the cases, a punctured insulator or coated insulator produces the high intensity ultrasound rather than emitting heat. Thus ultrasound is very effective in these applications to detect corona/arcing over other methods.
 "This method of detection during day time is added advantage over other methods like infrared imaging."

The Power Beam is very effective from 66 KV to 440KV Electrical system for finding out the faults with following applications.

Ø       Broken Strands.
Ø       Loose Hardware.
Ø       Improper Installations.
Ø       Damaged or Punctured Insulator.

Recommended Kit:

  • p/n 000041 - UL101 Corona Detector


How to inspect electrical panels

Electric Panel.jpg

Safety is the first line of defense. Scan cabinets & MMCs with panels closed. Use the CTRL UL101 Ultrasound Detector together with a airborne attachment. 

electrical arcing

Step 1: Scan with UL101 Ultrasound Detector
             Listen for arcing and discharge with panels closed
Step 2: Determine if Arcing Present
             Easily hear the arcing sounds from a safe distance
Step 3a: Open Panels with Confidence
               Safely open panels with appropriate PPE
Step 3b: De-Energize if Questionable
               High levels of ultrasound indicate severe problems


Recommended Kit:

  • p/n 000045 - UL101 Electrical Inspection Kit

  • p/n 000036 - UL101 Leak Detector Kit, standard

  • p/n 000038 - UL101 Leak Detector Kit, intrinsically safe


Contact CTRL

CTRL Systems, Inc.
1004 Littlestown Pike, Suite H
Westminster, MD 21157 USA
Phone: +1 (410) 876-5676
Toll Free (US): (877) 287-5797

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UL101 Corona Detector

UL101 Corona Detector