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AVEVA Pipeline Operations for Liquids

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Pressure / Flow Monitoring (Pressmon)

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  • Last UpdatedDec 01, 2022
  • 2 minute read

The Pressure / Flow Monitoring (Pressmon) application checks for unacceptable rapid changes in pressure, followed by a change in the behavior of monitored flow rates. Such changes are treated as the type of changes that may occur on a pipeline when there is a leak. The basic algorithm that the application uses to determine changes in pressure is illustrated in the Pressure Change Prediction figure below.

Pressure Change Prediction illustration.

The Pressmon algorithm follows these basic steps:

  1. Predict the next pressure value by calculating the slope of the pressure line and extending the line to the next sample time interval. This uses a configured number of previous telemetry values (up to 15).

  2. Compare the next telemetry pressure value to the predicted pressure. If the two differ by more than the deadband (+/- DB1) perform step 3. Otherwise, repeat from step 1.

  3. If +/-DB1 is violated, predict the next pressure value. Use deadband range +/-DB2 for the second comparison.

    1. If there is no violation of the second deadband after a configured number of iterations refer to Control (Algorithm) information in the AVEVA Pipeline Operations for Liquids Controller documentation and return to step 2.

    2. If there is a violation of the second deadband, issue a pressure alarm and an event, proceed to step 4.

  4. If a pressure violation is present, continue to predict pressures and start to predict flow rates. Flow rate prediction uses the same algorithms as pressure prediction, and two deadband ranges as well. Refer to the Flow Rate Predictions figure below.

    Flow Rate Predictions illustration.

Administrative staff will have configured step 4 in one of two ways:

  • Method 1: Check for flow rate violations for a set number of minutes. If no violations of the second deadband occur, return to step 2.

  • Method 2: Check for flow rate violations. Stop checking if the pressure value returns to within the second deadband. In this case, there will never be a flow rate point in alarm when the pressure point is not also in alarm.

If a flow rate violation of the second flow deadband occurs with either method, AVEVA Enterprise SCADA generates a flow rate alarm.