See Also
The following classes of inequality constraints are enforced during the SCOPF solution.
Generator real power limits
Generator real power limits are enforced during the SCOPF LP solution.
Generator reactive power limits
Generator reactive power limits are enforced during the SCOPF LP solution.
Interface MW Limits
Interface MW limits are enforced during the SCOPF solution. Interfaces are used to represent the aggregate flow through a number of different devices. During the SCOPF the MW post-contingency flow through the interface is constrained to be less than or equal to a user specified percentage of its limit, provided the interface is active for enforcement. For an interface to be active for enforcement the following three conditions must be met:
- Interface enforcement must not be disabled for the case. This field can be set from either the OPF Constraints Dailog or the OPF interfaces records. As default, the interface enforcement is not disabled. Note that interface flow is limited to a percent of its limit as specified by the interface's Limit Monitoring Settings.
- Interface enforcement must be active for at least one of the interface's areas. Note, an interface is assumed to be in each area that contains at least one of its components. This field can be set from the OPF Area Records display. Note: the default is that interface enforcement is not active, so be sure to activate this if you want these constraints enforced.
- Enforcement must be active for each individual interface. This field can be specified from the OPF interfaces records display or in the Limit Monitoring Settings dialog. The default is active.
Each interface that is active for enforcement is modeled as an inequality constraint, which may be either binding or not binding. If the constraint is not binding then it does not impact the solution. If a constraint is binding then it has an associated marginal cost of contingency enforcement. When manually solving the SCOPF one can skip a contingency violation associated to the interface by setting the Include field of the SCOPF CTG Violations dialog to No.
Transmission Line and Transformer (Branch) MVA Limits
Transmission line and transformer (branch) MVA limits are enforced during the SCOPF solution. During the LP the post-contingency branch line flow is constrained to be less than or equal to a user specified percentage of its limit, provided the branch is active for enforcement. For a branch to be active for enforcement the following three conditions must be met:
- Line/Transformer enforcement must not be disabled for the case. This field can be set from either the OPF constraints dialog or the OPF Line/Transformer Records display. The default is that case line/transformer enforcement is not disabled. Also note that the branch flow is limited to a percent of its limit as specified by the branch's Limit Monitoring Settings.
- Branch enforcement must be active for the branch's area. Enforcement for tie-lines must be active for either area. This field can be set from the OPF Line/Transformer Records display. The default is that branch enforcement is not active, so be sure to activate this if you want these constraints enforced.
- Enforcement must be active for each individual branch. This field can be set from the OPF Line/Transformer Records display or in the Limit Monitoring Settings Dialog. The default is active.
Each branch that is active for enforcement is modeled as an inequality constraint, which may be either binding or not binding under contingency conditions. If the constraint is not binding then it does not impact the solution. If a constraint is binding then it has an associated marginal cost of enforcing the contingency constraint, which is shown on the SCOPF Bus Marginal Price Details dialog. When manually solving the SCOPF one can skip a contingency violation associated to the branch by setting the Include field of the SCOPF CTG Violations dialog to No.