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Water System Operations Made Easier

Enriching SCADA Data Through Hydraulic Modeling

A Bentley Technical PaperPerrine Parrod, M.S., M.B.A.

Senior Product Marketing Manager, Water

Published: February 2016

Water System Operations Made Easier 2

Introduction

Traditionally, water system operators have relied on SCADA systems to provide insight into their networks. However, while SCADA systems have many benefits, they also have limitations. For instance, they do not allow operators to foresee the consequences if operations are altered in the future, and they require a sensor at every location from which data is required. While operators could theoretically go out in the field to test a different operation and examine its results, in reality this is generally unfeasible as it could have considerable negative consequences and can also be very time consuming and costly. Generally, operators need to have a clear idea of the consequences of altering any operations within the system before making these changes.

Hydraulic models, on the other hand, can calculate any point in a model system regardless of whether a sensor is present, by filling in gaps between measured points. They can also be used to test various operational alternatives, which is beneficial for planning, design, and operation projects. However, there are also limitations with hydraulic models. For example, a hydraulic model does not know the system status in real time (i.e., current pump status, tank levels) and it cannot predict any future boundary conditions.

However, by integrating hydraulic modeling and SCADA data, operational professionals, both operators and operation engineers, can overcome these limitations.

This paper reviews the latest Bentley software tools and technology, including SCADA-hydraulic modeling integration, which empower operators and operation engineers to more effectively improve the operations of the water systems they control. The paper focuses on how hydraulic modeling results can be leveraged by all operation personnel and benefit system operations in various ways, from improving energy management to enhancing shutdown planning and emergency response.


Benefits of Full SCADA and Hydraulic Modeling Integration

This section describes the strengths of integrating SCADA and hydraulic modeling solutions, and how operation and engineering professionals can benefit from this integration.

Benefits for Engineers

Integrating and utilizing SCADA data within hydraulic models allows engineers to create more accurate models that reflect real network conditions. These models can then be used to make more informed decisions about water systems.

Improved Model Calibration SCADA data can be used to provide the initial conditions for hydraulic modeling (i.e., the initial water system status). With the SCADAConnect® tool included in Bentley’s WaterGEMS®, SCADA data can be automatically integrated into the modeling software. This allows the designer to create a fully calibrated model of the water system in which the model’s results match the measurements taken by SCADA sensors.

The hydraulic model can even be calibrated continuously. This ensures that the boundary conditions used in the hydraulic model are updated with the latest real-time data to ensure that model results match SCADA data. This means that the model is automatically recalibrated if conditions change. It also reveals any divergence in the real-time SCADA data from the hydraulic model, so that changes and faults within the system can be detected as soon as they occur. This allows engineers to respond quickly to minimize downtime and keep the water system operating at maximum efficiency. Differences between the SCADA and model data also enable forensic studies of the system.

Forensic StudiesThe SCADA node element in WaterGEMS enables users to view both real-time and historical SCADA data and see the difference between SCADA and model results. Historical SCADA data can be used for forensic studies. A forensic analysis of the system can be undertaken by looking at historical data and viewing past events. For instance, the operator can review a past fault event, such as a main break, by viewing the SCADA data from the date and time the break occurred and examining the state of the system (e.g., pressure levels, pump status, and so on) at the time. This can help them identify conditions leading up to and during faults so that they can anticipate and plan maintenance and other operations. Forensic studies of the system can also be useful during the operator training process.

Real-time ModelingThe comparison of SCADA data and model results enabled by the WaterGEMS SCADA node element also displays alarms within the hydraulic model. Strong visualization capabilities in WaterGEMS empower hydraulic modelers to monitor SCADA signals as they change in response to real-time events. Overall, WaterGEMS enables users to confidently align their hydraulic models with real-world conditions.

Differences between the SCADA and model data also

enable forensic studies of the system.


Benefits for Operators

Filling Information Between SensorsIntegrating hydraulic model results with SCADA can fill in the information between SCADA monitoring points (for example, the expected pressure at a pressure zone boundary) and also provide operators with properties that can’t be measured directly (e.g., water age, velocity), giving them a more comprehensive overview of their water system.

Forecasting OperationsWhile the SCADA system alone only measures the current conditions in the water network, when combined with hydraulic model results it can be used to inform operators about how the network will respond to any changes that occur in the future (e.g., change of pump status, emergency response, and so on). The model can be used to test alternative ways to operate the system to save energy or improve efficiency, or can be used to examine operational responses to non-typical events such as fires, pipe breaks, power outages, and non-standard demands.

Seamless Integration for Easy VisualizationWaterGEMS software enables the visualization and manipulation of hydraulic results directly within the SCADA control (or human machine interface [HMI] screen). The SCADAConnect Simulator in WaterGEMS enables model results to be published to the utility’s existing HMI screen using the industry-standard OPC communication protocol. This allows system operators to visualize model results in a familiar interface.

Figure 1: Any prediction is are viewable on the HMI screen.

The software also provides operators with simplified control over the hydraulic model results. This enables operators to easily and rapidly test the network response to specific events or operation changes in a format they are familiar with.

WaterGEMS provides operators with simplified

control over the hydraulic model results. This enables

operators to easily and rapidly test the network

response to specific events or operation changes in a

format they are familiar with.


Figure 2: The SCADAConnect Simulator provides an interface that operators can easily use to test various alternatives.

Use Cases of Hydraulic Models in Operations

This section will review various instances where water professionals at a water utility can use hydraulic modeling results to improve network operation.

Atypical Days

Operators can use hydraulic models to visualize how the water network would respond to unusual conditions or events, such as a sudden increase in demand or an emergency shutdown.

Unusual DemandsAtypical demands include any scheduled events where the level of water demand varies greatly. Such demands may be created by a sudden increase in the number of people using the network due to concerts, festivals, sporting events, strikes, spring breaks, and more.

Using SCADAConnect, operators can easily adjust the typical water demands and override controls in the model to test various alternatives and visualize how their water network would behave under atypical conditions.


Figure 3: The SCADAConnect tool enables easy adjustment of water demands and controls to predict and visualize network response.

Emergency Response Decision SupportShutdowns are also part of atypical days, whether scheduled (maintenance) or unscheduled (pipe break, fire, power outage, contamination). In these cases, hydraulic modeling can help operators respond appropriately.

For example, by utilizing insight from hydraulic modeling results, system operators may better manage shutdowns by answering the following questions:

• What is the impact of shutting down some valves in the system?

• How does the water get past an area that has had a shutdown?

• Are there other mains parallel to the one being shut down that can service the system without problems occurring, or is shutting off a valve going to cut water service?

• How long can downstream tanks support the demands of the downstream customers?

Operators can use hydraulic models to visualize how the

water network would respond to various unusual conditions or events, such as a sudden

increase in demand or an emergency shutdown.


Figure 4: In complex networks, a shutdown map similar to this one can be provided to operators. Because of valving at the intersection of Belleville Dr. and Comuta Ln., all of the customers in the green box would be cut off from water, not just those served directly by the pipe with the “X.”

By combining the real-time information from a SCADA system with the power of a hydraulic model to interpolate and extrapolate system behavior, decision makers in operations can obtain a much more comprehensive understanding of measures to deal with emergencies, allowing them to respond quickly and effectively. As a result of Bentley’s SCADA-hydraulic modeling integration technology and enhanced collaboration between engineers and operators, response time and customer complaints can be significantly reduced and operational decisions improved.

Typical Days

Energy SavingsThe energy pumps consume for water distribution is a significant operational cost for water utilities. However, savings can be realized through applying various strategies identified and assessed in hydraulic models. Hydraulic models enable operators to determine where energy is wasted so they can:

• produce accurate system head curves to size pumps properly;

• run compatible pump combinations;

• evaluate the effects of oversized pumps and display efficiency variations over time;

• use the best energy rates;

• identify optimal pump operation schedules;

• reduce carbon emissions, and much more.


Figure 5: Pump combination display in WaterGEMS hydraulic modeling software.

Hydraulic modeling results enable operation teams to determine pump operating costs and to modify operations ensure that the best energy-saving strategy is implemented.

FlushingFlushing simulations in hydraulic models and various reporting tools allow operators to determine where flushing will be successful, as opposed to resorting to a trial-and-error approach in the field.

Useful reporting tools include:

• Flushing color-coded maps showing velocity in each pipe; and

• Flushing field reports, including drawings and instructions.

Figure 6: Specific flushing planning reports in WaterGEMS that can be distributed to operators.


Pressure ComplaintsOften, customers at lower elevations within a particular pressure zone receive water at a pressure that exceeds their requirements. This is a result of the way that the boundaries of pressure zones are arranged within the network. By moving pressure zone boundaries by modifying valving, these customers can be moved into a lower pressure zone and still receive sufficient pressure. This means that less water needs to be pumped into the higher pressure zone, reducing energy consumption. Lower pressure also poten-tially reduces the likelihood of leakage. On the other hand, customers receiving low water pressure may benefit from the zone boundaries being adjusted to place them in a higher pressure zone.

A WaterGEMS model can be used to color-code customers within a pressure zone by the pressure they receive and highlight customers receiving excessive pressure located along pressure zone boundaries. This shows operators the customers that can be moved to a lower pressure zone while still receiving sufficient pressure.1

Figure 7: A color-coded map in WaterGEMS, showing customers with excessive pressure along the pressure zone boundary. Magenta nodes are in the higher zone, blue ones in the lower zone, while red ones are in the higher zone but have high pressures and may be better off being moved to the lower zone by adjusting valves.

Operator Training

Publishing hydraulic modeling results on an HMI screen can also be used when training new operators. The models can be used to show a new operator how the water system is going to behave in response to certain operations or if a certain event occurred. Providing predictions in a familiar format enables training by communicating to operators in a way they can easily understand.

Flushing simulations in hydraulic models and various

reporting software allow operators to determine

where flushing will be successful, as opposed to

resorting to a trial-and-error approach in the field.

1 White Paper: Energy Savings in Water and Wastewater Systems, Dr. Thomas Walski, Tony Andrews, July 2015

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© 2016 Bentley Systems Incorporated. Bentley, the “B” Bentley logo, SCADA Connect and WaterGEMS are either registered or unregistered trademarks or service marks of Bentley Systems, Incorporated, or one of its direct or indirect wholly-owned subsidiaries. Other brands and product names are trademarks of their respective owners. CS 4896 0116


Conclusion

Engineering–operation Collaboration Improves Decisions

SCADA and hydraulic modeling technologies are both very useful when used independently. However, they also have their limitations. Innovatively integrating SCADA and hydraulic models and setting up automatic workflows benefits modelers (planning or engineering departments) and operation teams. Overall, by leveraging the information made available through engineering–operation collaboration decision making can be significantly improved.

Slow Integration Adoption

Currently, the adoption of such integrative approaches is slow, and collaboration between engineers and operators is not widespread. This is due to setbacks such as security concerns related to firewalls and permissions, and read-only access; and the different personas and approaches between the engineers doing the modeling work, and operation personnel in the control room or in the field.

For engineers, hydraulic modeling is both an art and a science, where the model elements are not necessarily representative of the exact structures in the field. This means that sometimes engineers use approximations in the hydraulic model in order to obtain network behavior that is the similar to what would happen in reality. These modeling conventions can be very confusing and look “wrong” for an operator. Operators typically have a “feel” when an element does not run properly or for how the network will react to a different operation2. As it is not unusual for one to dismiss the strengths and approach to work of the other, it comes as no surprise that frictions between teams may arise and affect the integration of SCADA and hydraulic modeling technologies.

Increased Return on Investment for the Utility

All things considered, when engineering and operation teams leverage each other’s technology and expertise, not only does this improve decision making for each group, but a utility can realize a greater return on its existing technology investments.

2 White Paper: Hydraulic Forces, Randy Rosbury, 2010 Water Environment Federation

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