Demand inversing in SCADAConnect Simulator

   
  Applies To 
  Product(s): WaterGEMS, WaterCAD, HAMMER
  Version(s): 08.11.05.61, 10.00.00.XX
  Area:  Modeling
  Original Author: Scott Kampa, Bentley Technical Support Group

 

Problem Description

How can you use the demand inversing tool in SCADAConnect Simulator, to calculate and assign demands to nodes based on metered flow data?

Recommended Solution

Demand inversing is a legacy workflow used in older version of SCADAConnect. To include legacy items, refer to the following support solution:

How to access legacy SCADAConnect tools

Note that the above only works in models that previously used the legacy features in older versions. An improved demand inversing feature is being considered for a future release (reference # 83834)

Demand inversing is a method to adjust the assigned pressure junction demands in the water model to accurately match the real world demands. To calculate the real demands, Demand inversing requires the user to identify the boundaries of each zone, the inflow and outflow points, the tanks signals, and the SCADA tag associated with each value needed.

With this information, and SCADA data for a full day, the real world total daily demands of each zone can be calculated. The application can then find a multiplication factor that can be applied to each pressure junction's demand field in the model to make the simulated zone demand equal to the real world demand for that day.

Note: To run this tool, you must have one or more Zones defined in your model.

To use the Demand Inversing tool, the usual steps consist of:

1) Open Demand Inversing tool (within SCADAConnect, Tools > Demand Inversing).

2) Update all the tabs (Calculations, Reference Consumption, Flow Signals and Tank Signals) as necessary. See Demand Inversing Dialog Box. Make sure that the zones for which demands are being calculated have been selected in the "Reference Consumption" tab.

3) Go the Compute menu and execute "Estimate Zone Flow" or "Demand Multiplier." The Estimate Zone Flow command will compute the model over a 24-hour period and calculate the Estimated Daily Zone Demand Volume value in the "Reference Consumption" tab. This can be useful if the daily zone demand of the physical system is known and you want to manually compute a user-defined demand multiplier that can be applied to the demands. More often the Demand Multiplier command is used, which computes the Estimated Daily Zone Demand Volume value as described above, but also reads the SCADA data from a given day and calculates the Daily Zone Demand Volume from SCADA data value. It then does a simple calculation between the estimated daily flow and the measured SCADA daily flow to come up with a Demand Multiplier.

4) To have SCADAConnect create or update a demand alternative, go to Update and click on "Write Demands." This will update the demand alternative by applying the Demand Multiplier to every input demand value in the selected zone of the model, make the simulation's demand usage match the data gotten from the physcial system. If no errors are encountered in the process SCADAConnect will and issue a message "Demand Alternative ("name") Successfully Created." If the demand alternative does not show up in the alternative manager, click to Expand All in the alternative docking manager to force a refresh of the tree.

See Also

SCADAConnect Simulator

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