How New PD Technology Can Make You Hero Of The Day

The electrical field testing business can be very trying. Often our work involves long, lonely hours. These hours may be far from home and sometimes in difficult environments or circumstances, or perhaps be under ambitious time constraints. For numerous reasons our best-made plans may require modifications and adjustments along the way, making quick thinking, knowledge of new technologies, improvising, and changing courses necessary to meet customer demands.

So why do we continue to endure these challenges? Reward. While monetary reward is appreciated, the satisfaction of knowing that you did a good job is what brings us back time and time again. And, every once in a while, there is that especially gratifying reward when we are actually the hero of the day.

Recently, I was in the field to perform cable partial discharge testing at a campus-like facility, consisting of an extensive 15kV class underground distribution system. This is a task I have performed hundreds of times, but this day, I was armed with the latest, most advanced cable partial-discharge testing technology. Having thoroughly studied this new technology in advance and conducted some dry run experiments in the lab, I was cautiously optimistic about how the day would go. Given that this new technology was not well known to my customer, I was also conscious of the fact that they would be looking over my shoulder throughout the day, evaluating both my work and the new PD testing equipment.

Previous cable testing had been performed by another testing firm using standard PD test equipment, which did not fulfill expectations. Most recently, use of a standard PD testing instrument resulted in misdiagnoses of noise signals for PD. at led the customer to unnecessarily replace a perfectly good segment of cable and several good terminations, costing significant time and money. During this testing procedure, I explained the difference between the standard technology and the wavelet technology. As the day unfolded, the customer seemed optimistic and open-minded regarding the new technology.

Not much has been written about on-line cable PD testing because little has changed in the last several years. Recently, new advancements in computer algorithms have allowed for the recognition of small and moderate PD pulses in 

heavy noise conditions. Having given up that this breakthrough would ever occur, my last cable PD column (NETA World Journal, Winter 2012) discussed the use of standard PD testing equipment, the need for filtering, and the compromises that must be taken in heavy noise conditions. These compromises include inhibiting the ability to look down the cable and only allowing the technician to “see” components close to the test point.

With partial discharge wavelet technology, these limitations no longer exist. As shown in Figure 1, newly perfected software can now detect pulses characteristic of PD “underneath” the noise.

PD-like waveforms are spotted by the software deep within the noise and separated out on the instrument display panel. The technician can click on the PD waveforms highlighted on the instrument’s display panel, analyze the computer’s assessment, and make final PD verifications (see Figure 2). The new technology is easy to use, makes system diagnostics nearly automatic, and the identification of PD much more accurate.

Often spending grueling hours at the customer’s campus, on this particular Friday afternoon, I was happy to complete the job in only a few hours and jump into my air-conditioned vehicle for the 90-minute drive back home against Los Angeles traffic. Unfortunately, there was an auto accident that added an hour to the journey, making it still a 14-hour day. But when I arrived home, I was still in good spirits from the gratifying day's work and the knowledge that new technology is always a beautiful thing.

As I sat down at home to remove my dusty shoes, my cell phone buzzed indicating a new email. I sat back, and as I read the following message from our customer and reflected on it, a tear came to my eye.

" Don,

Thanks for coming out today. What you do is so appreciated — you have no idea.

It makes one feel there is real care and hope for being able to manage a medium-voltage system.

You have no idea how much we appreciate your expertise, professionalism, and ability, and we know one thing for absolute certain — advancing this developing science of effective partial discharge analysis is going to save many innocent people’s lives in the future and many innocent people’s professions and careers as well. Nothing could be more sincere and from the heart because you know it's true what a difference this will make. I know this can be a truly thankless profession, but you're really doing something that broadly helps, even if many of those being helped don’t even necessarily know it, and this is NOT taken for granted. "

Next time, it might be your turn to be hero of the day. Covet those times, and don’t forget that for every thank-you and smile that we receive from our customers, there are many other times that they feel just as much appreciation, but do not express it. Of course, we understand that the electrical testing technician’s job is important, saves lives, and ensures reliability, so we don’t necessarily need a pat on the back. I guess that's why we keep coming back.