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Thread: VFD Pumps

  1. #1
    Member
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    Apr 2015
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    VFD Pumps

    Hi,
    Looking for some assistance (best practices) in modeling Variable Frequency Drive Pumps. Have several in our distribution system.

    How are users modeling these pumps where the power/speed is adjusted based on the flow?

    Thanks

  2. #2
    Senior Member

    Innovyze Employee



    Join Date
    Feb 2013
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    146
    Hello Shawn,
    Is this question for InfoWater or InfoSWMM?
    Best,
    Robert Dickinson
    Innovyze

  3. #3
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    Sorry, InfoSWMM.

    Thanks

  4. #4
    Senior Member

    Innovyze Employee



    Join Date
    Feb 2013
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    Hello Shawn, it you want to change the pump speed, you should use RTC rules to change the Pump Setting which is the pump speed. Here is an example

    An oft requested feature in SWMM 5 is the ability to better simulate a variable speed pump. The basic feature we are trying to model is multiple pumps between two nodes, one pump curve for all of the pumps and the ability to turn on and turn off the pumps based on either the head or depth at a Wet Well (Figure 1). You can turn on or off the pumps Pump1, Pump2 and Pump3 based on the depth at the Wet Well but this feature is stepwise linear and usually uses three pump curves. A better way to simulate this feature is to use the SWMM 5 Real Time Rules (RTC) to simulate the Pump setting based on a control curve.

    The Pump flow at any time step is the Pump Flow estimated from the Pump Curve (Figure 2) * The Pump Setting (Figure 3)

    Each of the three pumps has a different Control Curve (Figure’s 4, 5 and 6, respectively) which turns on or turns off the Pump based on a range of Wet Well Depths. The overall effect is that the total flow summing all three pumps together is smoother (Figure 7 and Figure 8) and the user can simulate different pump speeds based on the same pump curve depending on which pump is currently on.
    https://swmm5.org/2013/07/23/smoothe...tion-of-a-vsp/

  5. #5
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    Join Date
    Apr 2015
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    Thanks Robert. I'll have a closer look at my pumps & pump curves and apply some of your suggestions.

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