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CTRL Ultrasound Listening Device

Ultrasound Listening Device (ULD) Benchmarking on Electrical Facilities

The Case

A major brewery with international presence and plants all over the Mexican Territory has a issue where different ULD (Ultrasonic Listening Device) are implemented in several sites. One plant in South Mexico is a current user of the CTRL UL101 and InCTRL platform. The plant constantly works with the CTRL Systems equipment and have found many events that would have been difficult for normal senses or a vibration analyst to detect and diagnose. This plant is running smoothly with the UL101 Troubleshooter and the InCTRL platform, so their success became well-known within the corporation and reached other locations.

One of the plants in the Northern Mexico that has been working with other brand pistol-type equipment for years and reached the date for ultrasonic inspection on their electrical assets. The inspection is exhaustive, including electrical service drop, substations, CCMs, dry (air-cooled) transformers, switchgear and all kind of electrical equipment. The plant used a parabolic dish 32 to 40 ft. from the main structure of the service drop. Throughout the years, the equipment became damaged but the plant was told by the manufacturer that their equipment was obsolete, and that they needed to purchase a new one. The ULD was working, but communication with the memory card was not functional, so they could not make any recordings and deliver the proper reports.

For the plant to make the investment for a new equipment was not a simple task. Despite having a lot to share on savings that were made with the ULD equipment, the corporation demanded a lot of requisites. This task is easier to complete with a CAPEX compared to an OPEX, but the corporation was not on time to put the acoustic ultrasound equipment on capital investment. Thus, equipment failure was not prevented.

The Borrowing

All plants on the corporation communicate with each other, and the maintenance group shares information and good practices as part of a continuous effort to improve the developing RCM (Reliability-Centered Maintenance) systems.

The Northern plant communicated the disengagement of their ULD with the entire maintenance group. The Southern plant informed about another ULD that they successfully implemented: the CTRL UL101 Troubleshooter Kit and the Power Beam 300 (Parabolic Dish). They told the corporation about the benefits of CTRL’s ULD, including the fact that it is less expensive. Furthermore, it has helped to improve the sensibility and noise-to-signal ratio in their experience. The Southern plant broadly recommended the UL101 for electrical and long-distance inspections and for Mechanical CBM, which was one of its big uses on the South Plant.

The Northern plant asked the Southern plant if they were able to borrow the equipment for a routine programmed inspection that they needed to execute on the service drop, substation and switchgear. The Southern plant was not happy to let the equipment go, even for a week. But the request was made from a manager who pressed the Southern Plant to lend it, assuring its prompt return within one week. The equipment was prepared to be sent, and as the UL101 hard case is small and portable, it was easy to send over a freight company.


The deadline of the inspection was met, and the UL101 surpassed the expectations. The UL101 had better reception and sensibility, and was able to catch three Corona discharges that the other parabolic dish could not detect. Corona is a discharge that creates an electrical field and energy that can lead to acceleration of aging in the long term, and can generate damage on the insulators and destabilize the power system operation. This discharge generates an ionization field across the components that create a chemical reaction on the air. With the presence of humidity, the discharge increases in intensity and creates nitric acid, which is a very corrosive agent for all dielectric and metallic parts that come in contact with it.

Corona can be both destructive and not, but it could lead to damage. It is important to consider the fact that Corona can be also be produced by design flaws or poorly carried out maintenance works such as sharp edges, projective points, and bad installation features. Although this is not directly a destructive damage, on a long-term basis it will lead to insulation corrosion, erosion, and physical damage. Corona discharges are well known causes of power loss in the system.

The UL101 measured and captured Corona Discharge on service drop and the insulators of all substations at distances not met with prior equipment. It also helped the plant detect problems and document with the InCTRL platform, leading to a better quality of periodical inspections by using Ultrasound on their electrical assets.

They also inspected enclosed switchgear and transformers using the UL101. Ultrasound is a great tool and helps improve the security of the inspection and fulfill the NFPA 70E standard, since it doesn’t require opening any doors or guards to perform the inspection. Inside an enclosed electrical asset we could find electrical arcing, tracking (electrical arborescence), and mechanical looseness of any energized component.

The InCTRL Platform was key to doing this exhaustive work in less than one week, as long as all the information was recorded to the database and analyzed quickly. The technicians brought one mobile phone as a data logger and synced it with the cloud-based InCTRL system. Having the information on this new generation database helped them to develop an analysis and diagnose issues in record time; a huge improvement in comparision to the old data transfer model they were used to

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