Simulation settings

The settings in this tab are used to configure the simulation time-step, required parameters and execution for power-flow calculation, and parameters for dynamic simulation solver. For every configuration changed, click Apply before proceeding.

Time-step (seconds)

Regardless of the execution mode, Power-flow calculation or Dynamic simulation, a valid time-step must be defined in this field.

Ensure the Simulink model is set to use a fixed time-step (under Simulation > Model Configuration parameters > Solver).

Power-flow calculation

Initialization method	There are three initialization options available for power-flow calculation in the drop-down menu. From input data: The values specified in the network input data file are used. Flat Start: The power-flow routine assumes the initial voltage magnitude of all PQ buses to be 1 p.u. and initial voltage angle of all buses to be 0 degrees. Smart Start: A linear approximation of the power-flow equations is solved beforehand to provide a good initial guess to the Newton-Raphson method.
Power mismatch (max p.u.)	Termination condition based on the tolerance of the mismatch equations (default 1E-8). The algorithm terminates if the norm of the mismatch equation becomes smaller than the specified tolerance.
Max number of NR iterations	Maximum number of iterations allowed for Newton-Raphson to converge (default 100). If the algorithm does not converge once this limit is reached, ePHASORSIM stops and the error message “Power-flow didn’t converge” is displayed.
Execute	Runs the power flow calculation.
Execute and export report	Runs the power flow and also writes the results into following output files in a folder with name follows the format: '[XLS file name].PowerFlow'. 0_NetworkComposition.csv: Number of different components in the network (buses, machines, loads, etc). 1_Bus.csv: Bus types, base voltage, voltage magnitude, and angle. 2_Machine.csv: Machine PQ and Q limits. 3_Statistics.csv: Number of NR iterations done and largest power mismatch.

Dynamic simulation

Start from Power-flow	If checked, runs power-flow before running a dynamic simulation and the Solver initializes dynamic components based on voltage and power values calculated by power-flow. If unchecked, the voltages and power values in the input data are used for the initialization of the dynamic components.
Number of partitions	The solver can automatically partition the admittance matrix into a block bordered diagonal format to perform parallel simulation. This uses a graph partitioning method where the number of desired blocks is defined by this parameter (a positive integral number). Depending on the power system’s topology the value for this parameter varies. An ideal value for real-time performance can be sought using trial and error analysis. As a rule of thumb, the number of partitions should be 5-7 times the number of available CPU cores. For example, with 10 cores available, the ideal value is likely between 50 and 70. Refer to Parallel Simulation for more details.
Export admittance matrix	Writes the network’s admittance matrix as a CSV file with a name that follows the format: '[XLS file name]_Y.csv'.
Need more logs?	Displays instruction to get more logs and verbose output.
Optimize number of threads (Windows only)	Finds the optimal number of threads (in terms of run-time performance) to be used for the parallelization of both network solver and integration of genunits. Refer to Parallel Simulation for more details.

Note:

'XLS file name' refers to the name of the Excel file configured in the Network data tab.