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Modelling active control for PRV

Hi, I am struggling to find an option in WaterGEMs for the active control PRV. Basically, I need the PRV to asjust its downstream pressure to keep pressure at the remote node of the network constant.
Which options are available in WaterGEMs?
Thanks in advance

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  • Hello Anna, 

    Do you mean that you have set PRV in the model which is not functioning as expected i.e. downstream pressure is not reducing as per the setting of PRV? 

    Proper functioning of PRV depends upon surrounding hydraulics as well, if the pressure is already too low then it will not be able to maintain the set pressure. 

    Or you mean that you want to set controls for PRV based on say elevations, 

    How can I make a PRV/PSV active after closing it with controls?

    How does the Pressure Reducing Valve (PRV) work in WaterGEMS and WaterCAD?

    If this is not what you are looking for then please elaborate your query, also upload model files if required. 

    Sharing model files

    Regards,

    Sushma Choure

    Bentley Technical Suppport

  • Thank you, Sushma

    I am working with urban water distribution network separated in DMAs. I need to set a control for PRV at the entrance of DMA which adjust the downstream pressure of PRV acording to the pressure at the Critical Point of the DMA (I think sometimes this is called "closed loop control"). In reality this is done by installing Active Control by Critical Point (I2O for example). So, there is pressure sensor at the critical point of DMA which sends signals to the PRV, and PRV adjust its downstream pressure according to the pressure at the critical point, trying to keep it at the minimum required value (1.5 bar in this case). This is done in order to keep pressures inside DMA not higher than needed to provide minimum required pressures to all consumers.

  • Hello Anna,

    If you want to regulate pressures in a DMA based on your PRV setting you have to choose the "Pressure Setting" field and enter the appropriate initial pressure setting of the valve. Based on this the pressure at the downstream junction would be reduced.

    Since you are trying to control pressures in a DMA, it would be worthwhile to have a look at the below article;

    Modeling District Metered Areas (DMAs)

    Although you might have the DMA's already delineated, you can go through the "Option 2" under "Other Methods of DMA generation" in the above article. This can help you in understanding pressure regulation in DMA's based on the input data you have.

    Additionally you can also have a look at the Pressure Zone Manager tool to get an idea for pressure management;

    Using the Pressure Zone Manager

    Hope this helps.


    Regards,

    Yashodhan Joshi

  • I believe what you are saying is that you have a PRV that throttles based on a pressure somewhere else in the system, not at the immediate downstream side of the PRV. 

    In WaterCAD and WaterGEMS, PRVs can only monitor the pressure on the immediate downstream side, then throttle dynamically to maintain that setpoint. If you want to maintain a pressure somewhere else in the DMA, you may need to consider one of these options:

    1) Determine if there is a correlation between the pressure at the PRV and the pressure at the "critical point". For example if the critical point pressure setpoint is 1.5 bar and the pressure at the PRV discharge side tends to always be about 0.2 bar higher than the pressure at the critical point, then you could set the PRV pressure setting to 1.7 bar.

    2) Use a series of controls to change the PRV setting (or maybe a TCV headloss setting instead of a PRV) as the pressure approaches the setpoint, at the critical location. Basically achieve the desired operation with a collection of logical controls. This may be tricky and may require some calculation option adjustment.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Reply
  • I believe what you are saying is that you have a PRV that throttles based on a pressure somewhere else in the system, not at the immediate downstream side of the PRV. 

    In WaterCAD and WaterGEMS, PRVs can only monitor the pressure on the immediate downstream side, then throttle dynamically to maintain that setpoint. If you want to maintain a pressure somewhere else in the DMA, you may need to consider one of these options:

    1) Determine if there is a correlation between the pressure at the PRV and the pressure at the "critical point". For example if the critical point pressure setpoint is 1.5 bar and the pressure at the PRV discharge side tends to always be about 0.2 bar higher than the pressure at the critical point, then you could set the PRV pressure setting to 1.7 bar.

    2) Use a series of controls to change the PRV setting (or maybe a TCV headloss setting instead of a PRV) as the pressure approaches the setpoint, at the critical location. Basically achieve the desired operation with a collection of logical controls. This may be tricky and may require some calculation option adjustment.


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

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