Power Flow Solution: General
The following options are all contained on the General tab after choosing the Power Flow Solution page of the Simulator Options.
Assumed MVA Per-Unit Base
This option allows the user to specify the MVA base to be used for the entire case. By default, this value is set to 100 MVA. Click on the Change System Base button to change this value. Changing this value will update all of the internal structures to store the proper values on the new base.
Bus Loss Sensitivity Function
Bus loss sensitivities indicate how island or area losses change with power injection at the bus. Here you may choose to forego the calculation of bus loss sensitivities or to base them on island losses or area losses. If the case consists of only one island, which, by definition, corresponds to the entire system, then the bus loss sensitivities are measured with respect to total system losses. If the bus sensitivities are set to User-Specified, the sensitivities will remain at their last calculated values, according to the loss function type previously specified when the loss sensitivities were calculated.
Monitor/Enforce Contingent Interface Elements
This global location allows you to determine how contingency elements in an interface should be treated in Simulator. You can choose to never include the impact of contingent elements on interface flow, to only include contingent element impacts in the standard power flow or optimal power flow routines, or in all solution routines including contingency analysis and security constrained OPF.
It is not uncommon to ignore the impact of contingent elements when using the contingency analysis or security constrained OPF tools, as they are already processing lists of contingencies and evaluating flows on interfaces. Ignoring contingent elements within interface definitions allows for a determination of the impact of other contingencies on the flows of the non-contingent elements forming the interface, without impact from additional contingent element considerations.
There are some tools in which contingency elements in an interface are always ignored regardless of how this option is set. These include the following:
- Line Outage Distribution Factors (LODFs) Sensitivity Tool
- LODFs for interfaces containing contingency elements will be calculated based on the monitored branches only and the contingency elements will be completely ignored
- Contingency Analysis
- When using a linear calculation method or the case is in DC power flow mode an interface containing contingency elements will be completely ignored as a monitored element
- ATC Analysis
- Interfaces containing contingency elements will be monitored for base case limits, but will be completely ignored during monitoring for contingency limits
Power Units for Display
Shows which power units, Mega- units or Kilo- units, are used for displaying values. The units cannot actually be changed with this option, but this option can be changed through an auxiliary file.