The latest developments make it easier than ever for operators to decide how to minimize the disruption to customers. The quicker and simpler analysis is ideal for deciding on emergency responses, where broken pipes or plumes of pollution must be isolated as quickly as possible with minimal supply interruptions elsewhere. Use of the Shutdown Simulation helps ensure that isolating a section of the network will not cause unacceptable pressures elsewhere on the system.
Checking on pressure
The new shutdown analysis automates a number of processes so that simulations can be performed quickly and easily. Isolating a part of the network can create problems outside the affected area, either by cutting off the supply or by causing unacceptable pressure changes. InfoWorks contains a new, simpler method for analyzing the effect of a shutdown on pressures across the network.
Its use brings advantages as there is no need to change the existing network or the controls, giving quicker answers in an emergency situation. Previously, a special run would have been required, using changed control settings to ensure that all the isolated pipes would be excluded from the model.
With the new InfoWorks run type, Shutdown Simulation, the modeler selects a group of pipes to be closed and InfoWorks then carries out the hydraulic simulation and produces a report detailing what would happen if those pipes were not in use. It covers the entire selected area, which could be the whole model or a segment.
Isolation Trace and Isolation Analysis
The new type of analysis works alongside the existing InfoWorks Isolation Trace and Isolation Analyzer tools. These are used to determine the valves to be closed in order to isolate the problem and to check how this closure will affect the supply to the rest of the system. The hydraulic analysis is then carried out by the new Shutdown Simulation.
The Isolation Trace allows a user to select a pipe or pipes to be isolated and to identify which valves must be closed to isolate the problem.
Two different approaches can be used. One mode assumes that all the isolation valves are represented in the model. In this case the Isolation Trace will automatically produce the results using only network data. However, this is generally not the case. As few as 1% of valves control the water in normal circumstances - the rest are not vital to the model and so may have been omitted.
InfoWorks WS addresses this by enabling the simulation to be run interactively with the corporate GIS system. This shows the location of all valves, including those that are not in the InfoWorks model. The Isolation Trace is then used by the modeler in deciding which valves need to be closed. The Isolation Trace tool determines which pipes should be closed and which customers will be without water. It will also indicate if any special customers, such as dialysis patients, are affected. The link with the GIS system enables full contact details to be extracted for those affected.
Another well-established tool in InfoWorks is the Isolation Analyzer, which examines the closure’s impact on the rest of the system. The tool checks the connections in the system to determine whether any other areas would become disconnected following the proposed closures. This analysis does not involve any hydraulics - it simply checks through the network’s connectivity to identify other affected areas. The Shutdown Simulation is used to check the hydraulic effects of the closure.
The InfoWorks WS isolation and shutdown tools can also be applied to a merged model. This can be useful where neighboring utilities wish to collaborate to solve a supply issue. The isolation trace and isolation analysis should be performed before merging the models and the shutdown analysis can then be carried out on the merged network.