Model N-1 Security Constraints

Security constraints can be added to a production cost model to model the impact of branch outages (N-1 contingency) on active power flows. In SAInt, this is achieved with the help of contingency (CTG) objects and adding monitored branches (MBR) to the contingency.

This approach only works when the network event USESYSTEMBALANCE is present in the scenario.

1. Define a contingency

With the desired electric network open in SAInt, right-click on any branch and select Add New Contingency as shown in Figure 1. You can leave the name of the contingency as CTG_0.

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Figure 1. Creating the contingency object.

2. Add monitored branches to contingency

To monitor the active power flow on a branch under the contingency, right-click the branch and select Add Monitored Branch To Contingency  CTG.CTG_0 as shown in Figure 2.

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Figure 2. Adding monitored branch to contingency.

You can add multiple branches as monitored branches to a given contingency. After selecting the desired branches, right-click on one of them and select the Add Monitored Branch To Contingency option from the context menu.

The default contingency CTG.DEFAULT can be used to model the N-0 case with no outages. If CTG.DEFAULT has no monitored branches, all branches in the network will be monitored.