Transcript

Introduction

Hello, everyone, and welcome to today’s White Paper Webinar. Today, we are here with David Horning to talk about using a Tensor in a greenhouse. We’re gonna show you how you can get useful information from a plug-in-the-wall PQ monitor. So, I’ll turn this over to David.

The Tensor in a Greenhouse Environment

Thank you. The Tensor is a very good device for diagnosing electrical problems at the outlet, at the  customer level. In this white paper, several things were plugged into a Tensor that a typical greenhouse would use. This is a small-scaled, backyard greenhouse, but uses the same kind of equipment you would have in a large greenhouse.

You have different components in the greenhouse, and we showed each one plugged in for a specific time, and showed the graphs in PQ Canvas where it was recording. This greenhouse went through Wi-Fi at the house, and reported to PQ Canvas.

Greenhouse Components and Current Draws

And so, if we look back on the recording, we can see the different graphs that were used, and you can see the actions that were placed on it. This is the section where I had an electric heater plugged into it, where the heater would come on there are traditional heating spikes. It was a 10-amp heater just to keep the greenhouse warm on certain days.

The heater is just a standard load. If you go back to the current draws, this was when a larger 15- amp heater was plugged in.

And there were different things connected to it like the exhaust fan, that would come on when the temperature gets above a certain level. We had a circulating fan just to circulate the air. And we had a warming mat. Essentially, all the components you would have in a greenhouse.

Temperature Monitoring and Alerts

We find that you can go back and see at different times what the temperature was, and how the fans and the heaters affected the temperature. As the heat came on, the temperature would rise, obviously.

Alerts can be set up so that when the temperature would drop, it would send an alert, and you’d have time to react. There were no alerts sent during the time because everything worked as expected. So, if the temperature dropped below 42 degrees, it would alert before the vegetables inside would freeze. Also, there was an alert set for power interruptions, so that if the power had gone out, you could take action.

Power Graphs and System Effects

We could also go back and look at the real power graphs to see, during the day, how much it is pulling in power during the time, how long it is on, and how long it’s off. So, we have different graphs all available based on the data.

The Tensor gives a whole system of a views because as the environmentals- humidity and temperature, are affected by all the fans. When the exhaust fan came on, the humidity would decrease when it was hot. And when it was cold, when the heat came on, the humidity also decreased. It was a system effect.

Reviewing the Figures

We can see that if we go back to some of the figures where you’re showing some humidity and other environmental factors, in Figure 6, for example, in the top plot, voltage and current, the voltage in green, current in blue. And then we have temperature on the next plot, and humidity and pressure.

And of course, the pressure is based on ambient atmosphere pressure, but the temperature and humidity are, of course, closely related. As the heater would cut on, the humidity changes or vice versa. And you can see those blue current spikes or current step changes, that’s when the heater came on. And every time the heater comes on, you see the bump in the temperature and the drop in humidity that we were trying to control in the greenhouse.

And so, the Tensor is the perfect tool for that because we’re tracking the heater operation with the current. We’re tracking voltage quality, but also tracking temperature and humidity, which are key parameters in a greenhouse environment.

Figure 2: Exhaust Fan Effects

We also see another example in Figure 2, where we have the same type of plot where we have temperature on the second to the top, and then humidity there, and then atmospheric pressure, and current in blue. And you can see when the exhaust fan comes on, you see that the temperature starts to mediate, but the humidity drops when the exhaust fan and the heat comes on.

You can see really how all these are related with the Tensor, and if you’re especially trying to track some sort of control system, this is a great tool to do that.

Alert Configuration

Here we have the alert set-up for temperature set for 42 degrees. And again, the biggest temperature alert you need to react the quickest is if the temperature gets too cold and you wanna have your thresholds set up to where you have time to react before the temperature drops on a real cold day. And  in case your heater isn’t sufficient, you wanna know in time to do something about it.

The alert notification system allows e-mails, texts, and you can notify within a few minutes of the time it crosses, and your alert can have graphs of the last few hours, so you can see the trend as it comes. You don’t have to wait to go back and download a recording and look to see if it had gone out of control. You get the immediate notifications.

These can also be sent in text messages. You might have one that’s got low, low, and high, high. So you might set one alert based on some sort of operational thing you learned about, and then sort of a fail-safe that if it gets below a certain level that’s near catastrophic, and you wanna rush in and take charge immediately.

Using the Tensor at the Consumer Level

Since this is done at the consumer level, if the user is complaining that every time they plug in something, there’s a problem, the Tensor can see what is actually happening with that one item isolated, where you can’t get that kind of information at the pole. You can get it per device, and then see each of the devices’ effects on your current and voltage.

And where this might be useful for a utility is, for example, inside on a residential power quality plug, you might put the Tensor inside the house with a guardian or something else on the outside at the meter base or at the transformer secondary. And then because you have the environmental readings also, you can track, for example, if it’s an open or loose neutral, is it always happening at a certain temperature range or a certain humidity range?

Some electrical effects are dependent on temperature and humidity, even things like insulators on a pole that may arc or might have corona discharge that’s different based on air pressure or humidity, and the Tensor gives you a way to draw those correlations. If you see that you have, for example, voltage swings that tend to track with a certain temperature band or certain humidity band, the Tensor can help you figure that and determine that correlation, which will give you some clues as to the root cause.

Summary and Closing

That covers the white paper. The paper is about using the Tensor in this greenhouse environment and really leveraging the environmental aspects of monitoring that it can do and the alerts. But again, in terms of the larger picture of utilities, there are a surprising amount of power quality symptoms that vary based on temperature and humidity. Having that information can help determine a root cause.

If you have transients that are happening more often at a certain temperature, or a range, or where the humidity is high, for example, that can help point towards what it might be on the primary side, or if it’s a loose neutral, that can be usable too.

And of course, a Tensor without the environmental sensing is on its own a useful way of tracking power quality past the revenue meter, especially if you’re trying to demonstrate that there is a voltage quality issue, but it’s inside the customer’s own wiring and not as delivered by the utility. So that can help in conjunction with a recording outside the meter base. The fact that the voltage looks different inside can be very helpful in closing PQ investigations.

If you have a question later, give us a call anytime, at 1-800-296-4120. Thanks for attending, everyone and have a great afternoon.