Ultrasonic Screening: Inspecting Equipment You Cannot Open

Energized switchgear and distribution gear stay closed for good reason. Opening them takes qualified people, a safety plan, and often a shutdown.

So for most of the year, the interior of that equipment is missing from your facility record. Anything you can observe and document from outside is worth having.

Ultrasonic screening points to a condition worth looking into. It does not name the fault, pinpoint where it is inside the cabinet, or say how long it has been developing.

It works best on surface discharge, corona, and tracking. Discharge buried inside insulation may have no air path out and can go unheard.

What you hear also depends on background noise, where the listener stands, and the path the sound takes out of the cabinet. Treat a reading as a screening indicator that sends a qualified person for a closer look, alongside thermal and visual observation.

The most useful signal is usually the change from one pass to the next. That only works with consistency: the same listening position at the same checkpoint, the same instrument settings, and similar operating conditions.

Readings are relative, so a change in sensitivity between passes can look like a trend. Every reading needs a time and location so it can be compared with the last one.

A FacilityOps robot walks a fixed route through your electrical rooms. At each closed enclosure it stops at the same checkpoint and takes an ultrasonic reading at the vents and seams where sound escapes.

The robot uses the same listening position and the same instrument settings on every pass. That removes two common causes of false trends in manual screening: a different stance and a different sensitivity setting.

Each ultrasonic reading is captured with thermal and visual images of the same enclosure and logged with its time and location. A raised ultrasonic reading next to a warm seam tells a qualified person more than either reading would alone.

Each reading sits beside the same checkpoint's earlier readings, so a change is easy to see. When something changes, the exception goes to a qualified person, who decides whether the equipment needs a closer look or a planned outage.

The robot is what keeps the record consistent. The deliverable is a history of each closed enclosure that you can compare pass to pass.