The Reason For The Importance Of Partial Discharge Detection


When there’s a degrading insulation system, the possibility of partial discharges (PD) being the main reason for the issue is very likely. As such, this may result in extremely costly maintenance and can result in equipment failure.

After all, the appearance and magnitude of PD are crucial criteria to identify for the early detection of degrading insulation quality and evaluation of installed, manufactured, or repaired product quality. Moreover, it can be hard to interpret the PD data and determine the exact period when an insulation system may still be functioning before it’s damaged and leads to expensive maintenance.

Henceforth, regular PD testing plays an important role in being a dependable diagnostic method for detecting breakdowns in the insulation system of electrical equipment before any drastic negative impact or even a malfunction happens. But before we look into the importance of PD detection, let’s find out what PD exactly is.

What is partial discharge (PD)

Generally, partial discharges are small electrical sparks which appear within the insulation of medium and high voltage electrical machinery.

Every discrete partial discharge is the outcome of an electrical malfunction of an air pocket within the insulation. These discharges will corrode insulation and in due course, lead to insulation breakdown.

Partial discharge testing

Known as a major, leading indicator of machine breakdown – it is extremely crucial in identifying partial discharge in your equipment.

When a partial discharge is left undetected, chances of complete deterioration of the electrical insulation is highly possible, which will eventually result in force outages of motors and generators.

Hence, there’s a real need for PD testing to recognise any partial discharge and prevent service failures from occurring, extending the time between repairs and outages, and plan for servicing according to the equipment condition. Otherwise, when damage occurs due to the appearance of partial discharges – repairs like generator or electric motor overhauling may be needed; depending on your equipment.

Deals with measurement challenges

The signals released from PD activity may be of relatively small size, hence; comes the need for PD test equipment. With it, it’ll be possible for extremely high sensitivity detection and measurement.

However, this will also mean that while testing, it’ll be more prone to interference from electronic noise. Oftentimes, PD signals are superposed by noise pulses. Therefore, the PD data measurement is a lot harder for software systems and experts. This also makes minimising of disturbances one of the primary tasks when analysing PD in the field.

Moreover, as PD test equipment is known for its high sensitivity detection and measurement, a few methods of electrical noise suppression are utilised in demanding workplace conditions. The bandwidth and centre frequency can be adjusted for a dependable analysis, which is common with the freely-choosable filtering options. The multi-channel PD measurement is crucial for three or more procurement units.

As such, it will reduce the time of the high voltage applied during off-line testing, and the device will quicken the measurement time and allow the use of separation tools.

Evaluate insulation quality

With PD testing, technicians and engineers are able to diagnose an electrical system and insulation. It is the best action to take before an unexpected outage happens.

Using reliable and high-quality PD testing equipment, it is possible to prevent partial discharge as a whole. It is especially more crucial and effective when it comes to operating with high voltage machinery, and will even come in handy when it’s the manufacturing stage too.

It will assist in avoiding unwanted and dangerous incidents and provides periodical check-ups. Specifically, it will help to ensure that the electrical asset is safe to use.

While routine maintenance and unexpected repairs are both instances where servicing are necessary – be it transformer, switchgear or generator rewinding – it is not the same for partial discharges, as they can be avoided. Hence, check with a trusted engineer on when is the right time for a PD test. That way, you’ll be able to prevent any costly, unanticipated servicing.

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