Critical Link Analysis
Critical Link Analysis allows automated testing and reporting of the effects of failure of a selection of links. The time of outage and method of failure of the selection of links is defined. A simulation is run either for each selected link, or for each isolation area in the selection in turn. When running simulations for isolation areas, the link selection is checked for Isolation Area codes. A simulation will be run for each Isolation Area code found, closing all links with the same code simultaneously (regardless of whether the link is present in the selection).
Network nodes are tested against user defined Level of Service Criteria. By default, simulation results will be saved for each case in which link failure results in failure of nodes in the network to meet the Level of Service Criteria. The results can be viewed as Full Play results on the GeoPlan and as a Service Level Report.
The saved results can then be used to update the criticality fields of network pipes. The Criticality grade and Criticality Count values for the pipe provide an indication of the significance of the effect on the network if the link fails.
Alternatively, the criticality fields of each link being analysed can be updated at the end of the simulation for that link and the simulation results discarded. This option is of particular use when running Critical Link Analysis on a large number of pipes, as problems due to shortage of storage space for results files are eliminated. To implement this option, check the Update Criticality Only box on the Critical Link Analysis Options dialog. This option can only be used with a checked out network.
Running a Critical Link Analysis Simulation
To set up a Critical Link Analysis simulation:
- Set up the simulation as normal as described in Creating and Scheduling a Run.
- Set the Run Type option to Critical Link Analysis. The Critical Link Analysis Options dialog is displayed automatically when you first select this option. You can also open the dialog later using the Options button when Critical Link Analysis is the run type.
- Set criteria on the Critical Link Analysis Options dialog.
- Run the simulation as normal.
Critical Link Analysis Results
A base simulation will be carried out, followed by a simulation for each of the links or isolation areas selected in turn. The base simulation will be saved.
- If the Update Criticality Only option has not been selected simulations for the selected links that fail the Level of Service Criteria will also be saved.
- If the Update Criticality Only option has been selected, the criticality grade for each selected link will be updated and simulation results will be discarded.
