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Modeling a Variable Frequency Drive for a submersible pump

Hi, 

I would like to ask, how do I model a variable frequency drive (VFD) paired with a submersible pump? I have a 24-hour data of different pressure and flow reading.

Thank you

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  • You need to answer a few questions first.

    Are you in WaterGEMS/CAD or SewerGEMS/CAD?

    Are these pumps in the same wet well or are they far from one another?

    Does this mean that you have one constant speed pump and one variable speed pump at the same source?

    How are each of these pumps controlled in the real system?
  • I'm using WaterGEMS V8i. I'm trying to model an existing deep well with a submersible pump controlled by a variable frequency drive.
    In the real system the pumps are controlled such that during peak hours the pump would maintain 45psi at the discharge line and during night time the pump is programmed to maintain 20psi at the discharge line.

    There are no water storage in the system.
    Water is pumped from the deep well directly to the water network.
  • The wiki for modeling a submersible pump explains how to set up a submersible pump layout. For a VFD pump set the property of the pump for "Is Variable Speed Pump?" to "True", set the VSP Type to "Target Head", set the Target Head Type to "Pressure", and set the Pressure Target to either 45 psi or 20 psi depending on when the simulation start time takes place. If the control node is on the suction side of the pump set the property for  "Control node is on the suction side? to "True". To change the Pressure(Target) during either the peak hours or off peak hours a control will need to be set. The wiki here describes how to set controls. For example, the controls for this system might be like this:

    IF Clock Time  >= 9:00 PM  THEN PMP-1 Pump Pressure (Target) = 20.00 psi

    IF Clock Time  < 9:00 PM  THEN PMP-1 Pump Pressure (Target) = 45.00 psi 

    Regards,

    Mark

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  • The wiki for modeling a submersible pump explains how to set up a submersible pump layout. For a VFD pump set the property of the pump for "Is Variable Speed Pump?" to "True", set the VSP Type to "Target Head", set the Target Head Type to "Pressure", and set the Pressure Target to either 45 psi or 20 psi depending on when the simulation start time takes place. If the control node is on the suction side of the pump set the property for  "Control node is on the suction side? to "True". To change the Pressure(Target) during either the peak hours or off peak hours a control will need to be set. The wiki here describes how to set controls. For example, the controls for this system might be like this:

    IF Clock Time  >= 9:00 PM  THEN PMP-1 Pump Pressure (Target) = 20.00 psi

    IF Clock Time  < 9:00 PM  THEN PMP-1 Pump Pressure (Target) = 45.00 psi 

    Regards,

    Mark

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