Video: PD PROFILER – Technical guide

Video transcript

What is in the box, what each connector is for, how the sensors go on, how several units chain together, and how the software is set up. Before anything: this is equipment for high voltage environments, and the sensors go on live assets. The monitor itself is installed without a shutdown, but that only holds if the work stays outside the high voltage circuit. And the magnets are strong enough to pinch. What arrives.

The monitor with two mating interface connectors, the sensors you ordered, the coax leads, a kit of magnetic cable-tie mounts, a USB-C cable, the phase-sync module, acoustic coupling gel, and the software, which is free. The rear panel, connector by connector. Everything a sensor plugs into is a BNC, the two Ethernet ports let you chain units, and the two interface connectors carry power, synchronisation and the alarm in and out. Two indicators on the front and on the top, and they say the same thing.

Power tells you what the unit is doing; alarm tells you what it found. Blinking blue is you, from the software, asking the unit to identify itself. The two interface connectors are identical, one in and one out. Each has two pins for the 24 to 48 volt supply, one for the alarm, one for the sync signal and 4 for earth. Because in and out are wired straight through, a chain of units keeps power, alarm and synchronisation continuous.

Three ways to fix it, and they come fitted: rubber feet for a bench, magnets for a cabinet door or a switchgear panel, and a DIN rail bracket for a control cabinet. A rack version is also available. The phase-sync module turns a mains voltage into the low level synchronisation signal the monitor needs to build the phase-resolved pattern. Any AC reference from the network works, and the green indicator confirms it is powered.

The SonoTEV Pro. One sensor, two technologies: an acoustic sensor for airborne or contact measurement, and a transient earth voltage sensor under the overlay, with the magnets that hold it to the enclosure. One SMA connector, and the monitor powers the preamplifier through the same coax. One rule about this sensor matters more than the others. The amber film on the acoustic face is an insulator, and the sensor must never make direct electrical contact with the metal of the asset. Paint does not count. Keep the film on for every contact installation.

Remove it only for airborne installations where the sensor cannot touch the asset. The HFCT clamps around an earth conductor and measures the high frequency current that a discharge drives to ground. 20 millimetre and 60 millimetre openings, a spring latch, and 4 ferrite poles that must be clean when the clamp closes. A single unit goes together in this order. Earth first. Then the DC supply, then the phase-sync module, then the sensors on the channels you want.

Then you talk to it, over Ethernet or with a laptop on the USB port. For more sensors, units chain. One supply and one phase-sync module on the first unit, interface cables from out to in along the row, and Ethernet from unit to unit. The limit is voltage drop: the last unit must still see 21 volts. Cable terminations are the first application. The economical way is one HFCT around the combined earth straps of the 3 phases: one channel covers the compartment, but it cannot say which phase.

One HFCT per phase costs more sensors and gives phase-resolved results. A row of switchgear. One monitor, and a SonoTEV Pro on the outside of each cabinet, held by its magnets. External installation needs no outage, and the sensor hears the discharge through the cabinet wall. Inside the cabinet is more sensitive, but that needs a planned shutdown. A dry-type transformer. Two SonoTEV Pro sensors positioned at the ventilation openings,

with a line of sight to the active parts, and an HFCT on the transformer's earth conductor. Acoustic and electrical detection together. Commissioning is done from the PD Profiler Assistant, which is free. Connect the USB cable, and the unit appears as a box in the configuration menu. From there you name it, set the network and Modbus addresses, check the phase synchronisation, and configure each sensor. The acquisition settings are where the noise is beaten. For each sensor you choose the channel,

ultrasonic or high frequency, the duration, and a digital filter. Narrow band around 40 kilohertz for airborne acoustics, wide band for contact. On high frequency, a band-pass or high-pass filter takes the interference out before it reaches the pattern. And what the numbers mean, so that the alarm thresholds are set on something you understand. The specification, for the record. Partial discharge monitoring, from Amperis.