Analyze your pump performance curve in SCADAWatch with new Pump Efficiency module

Pump curve in SCADAWatch showing dramatic degradation over time.

SCADAWatch version 6.3 received a new feature for quickly plotting the performance of a pump along its pump curve.

This is information is critically valuable to three main groups of people (See more at The Stories your SCADA Data Could Tell You):

Managers – Save money by scheduling maintenance proactively based on data. Don’t waste energy running inefficient pumps.

Operators – Check whether your current or past operations are utilizing the peak efficiency point of your system pumps.

Hydraulic modelers – Update your water model based on current measured performance rather than outdated manufacturer’s curves.

This post walks you through how to set up a pump efficiency curve, compare it against reference data, and share it among your organization.

What do I need?

  • A data feed of flowrate through the pump(s)
  • Measured inlet and discharge pressures
  • (Optional) A data feed of pump setting or pump speed

Note as we get started: feel free to reference our online help for a more step-by-step tutorial.

Calculate the head difference

BizBlock schematic for headloss calculation

To make a proper pump curve, we need to plot the head difference contributed by the pump against the flow rate through the pump. Head difference isn’t a typical SCADA feed we can get directly, but in SCADAWatch we can easily set up a calculated feed that processes it in real time using a BizBlock.

Simply create a new BizBlock with a name specific to the pump (station) you are analyzing and add two inputs and one output matching the image to the right. Set the inputs as the measured inlet and discharge pressures respectively, then set the output using an expression like the following. Here we apply a factor of 2.31 to convert pressures of PSI to feet of head difference.

HeadDifference = ({@OutPressure}-{@InPressure})*2.31

Save, run, and review the results. This output will now be processed regularly as new data comes in, and it can be used in any charts or analysis. Furthermore, you can easily Clone the BizBlock to other pumps as well.

Plot the Results

Settings to plot pump performance for July 2016

Open the Chart tab of the SCADAWatch ribbon, and select the Pump Efficiency sub-tab. Set up the X and Y data to point to the pump flowrate and our above-calculated head difference. The BizBlock output should be called “HeadDiff – HeadDifference” if you used the names in the above steps.
Feel free to leave the speed curve and speed range unchanged for now, but be sure to chose a Time Range that spans a time when the pump is running. Also specify a small Data Interval such as 5 minutes or whatever you have available.

Clicking Add will produce a scatter chart of points that display the head difference against the supplied flow rate in the current SCADAWatch Workspace.

Go to the newly added pump curve chart and try out the following features:

  • Update the date range in the top bar to see how the pump performance varies over time.

    Example pump operation data against the manufacturer’s curve

  • Click Pump Efficiency Options in the lower right corner and enter in x,y points for the pump manufacturers curve (enter data points separated by comma).
  • Click Reference Chart in the upper left to add additional pump curves. You could either overlay pump performance from a time in the past to see the history, or add pump data from other similar pumps for comparison.

Filter out specific pumps from a station

BizBlock to filter out the status of only one pump at a time

In many cases, SCADA sensors might measure data in and out of a pump station, but not for each individual pump. Let’s say we have three pumps at our pump station that each have a status feed, but we only have one total discharge and one inlet and discharge pressure measurement. If we want to retrieve the pump curve for just one of the three pumps, we can filter based on pump status. However, to isolate one of the three pumps, we may want to use a BizBlock to create a new status feed that is on only when our selected pump is on and the others are off.

Create a new BizBlock with inputs of all the measured pump status feeds at your pump station. Then set up an output that uses IIF statements to only turn on when the desired pump is running. For example, the expression below will return 1 (“on”) when only status feed 2 is on and the others are off, otherwise the output will return 0 (“off”).

Selected_Pump = IIF( ({@Status1}=0) and ({@Status2}=1) and ({@Status3}=0), 1,0)

You could also set up an output feed for each n. This can later be easily used in pump curve reference charts to compare all the pumps side by side.

Share the results in your organization

The nice thing about working in SCADAWatch is that your work is on a web-browser easily shareable among your organization. You can choose among the following options:

  • Configure your Workspace to include other relevant information like a chart of the pump operations and a map of the location, then save the workspace and make it public so others that log in can view it.
  • Save your Workspace and click Share at the top. This creates a URL that can be directly shared with any that has network access to your SCADAWatch server and a log in.
  • Simply take a screenshot of the chart (this loses the advantage of being tied to live interactive data like SCADAWatch is).
  • Click download to get a CSV of the data used in the chart and set up your own graphics for reports outside of SCADAWatch.

Want more tutorials?

Visit our online help page HERE.


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    About Nathan Gerdts

    Nathan is a Client Service Manager and has helped utilities with training, implementation, and data review.
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