Solution

A solution describes the computed results for the variables of a network model for every calculated time point of a scenario. The solution of a scenario is saved to a solution file with the file extension *.*sol (e.g., *.esol for electric network solution, *.gsol for gas network solution, or *.tsol for thermal network solution).

Results are divided into "base" results and "derived" results. Base results are saved in the solution file. Base results comprise all fundamental results estimated and produced during a simulation or optimization run. Derived results are calculated from the base results. They are not written in an output file but calculated upon request by the user. For this reason, it may take a few seconds to build a chart or a table of derived results.

All base results are saved to the solution file. This means the user can always access whatever information is desired from any solution. For example:

  • An example of a base result for an electric line in a ACPF-scenario is the active power flow along the line P.

  • An example of a derived result for an electric line in a ACPF-scenario is LLP the line loading given as the ratio between active power (P) and maximum active power.

Consecutive executions of the same scenario files overwrite the same solution or state file.

1. Solution file

The "solution" file contains all the base results from the execution of a scenario. It can be regarded as an accumulation of states for every computed scenario time step. The name of a solution file is, by default, the same as the name of the scenario file that was executed. The derived results from the base results are not saved in the solution file to limit the size. Both derived and base results can be exported into an Excel file, visualized in customized charts and tables, etc.

The CEM solution files are currently available as CSV files in the same folder as the network and scenario file.

2. State file

A "state" (or condition) file describes the computed results for the variables of a network model at a specific time point and for a specific scenario type. It can be regarded as a snapshot of the scenario results for a network model at a specific time point. A state is saved to a state file with the file extension *.*con (e.g., *.econ for electric network state, *.gcon for gas network state, or *.tcon for thermal network state). The name of a state file is the same as the scenario name it is associated with.

The solution file is generated only for quasi-dynamic and dynamic scenarios. Steady state scenarios generate only a state/condition file. The state file of every non-steady state scenario is the terminal state of the solution file.

A state file can be used as an initial condition for a dynamic scenario.