This section contains the system MVA and a number of OneLiner and Power Flow system parameters. The first line in the section must say: [SYSTEM PARAMETERS]. This is followed by the data described below. A blank line ends the section.
Only the Base MVA item is required. The others are optional and can be omitted.
1. General etwork Parameters
Base MVA: The system per-unit base MVA. The default is 100.
SwitchX: Switch reactance in per-unit. Default is 0.001.
SwitchR: Switch resistance in per-unit. Default is 0.
LineB: Line capacitance emulation level. A value of 0 will cause the program to add the default amount of shunt capacitance to lines. Set lineB to 1 to use a smaller amount of capacitance. For more information, see the documentation of the Network tab of the File | Preferences command.
2. Generator Impedance for Short Circuits: This parameter tells the program which of the positive-sequence generator impedances to use for short circuit simulations: 0 for subtransient, 1 for transient, and 2 for synchronous. Zero is default.
3. Power Flow Parameters
The parameters following ‘pf=’ are for power flow simulations. The parameters are, in this order:
Maximum Iterations: The iterative solution will stop when the iteration count reaches this number, even if the power flow has not converged. The default value is 20.
MW Tolerance: The power flow is considered converged if the maximum MW and MVAR bus mismatches are less than their respective tolerances and the auto adjustment constraints (if any) have been enforced. The default value is 1.0 MW.
MVAR Tolerance: See explanation for MW Tolerance. The default value is 1.0 MVAR.
P Adj. Threshold: Real power adjustment threshold. This value is meaningful only if the LTC, MVAR-limit, area-interchange or remote voltage-control constraints are being enforced. The program checks and enforces these constraints whenever the maximum MW and MVAR bus mismatches are below this threshold and the Q Adj. Threshold, respectively. The auto adjustment thresholds (P Adj. and Q Adj. thresholds) must be at least twice as large as the convergence tolerances. The default value is 20 MW.
Q Adj. Threshold: See explanation of the P Adj. Threshold. The default value is 20 MVAR.
Enforcement Options: A bit field containing the automatic adjustment options used. The default is 0 for no automatic adjustments.
4. Short Circuit Parameters
The parameters following ‘sc=’ are for short circuit simulations. They are listed below:
Prefault Voltage option: 0 for “From linear network solution”; 1 for “Assumed flat”; and 2 for “From a nonlinear power flow solution”. 1 is the default.
Ignore Instantaneous: 1 to ignore the instantaneous unit of overcurrent relays; 0 otherwise. 0 is the default.
Ignore Loads: 1 to ignore loads; 0 otherwise. 0 is the default.
Ignore Shunts: 1 to ignore switched shunts and shunts with + seq. components; 0 otherwise. 0 is the default.
Ignore Line G+jB: 1 to ignore the shunt admittances of transmission lines; 0 otherwise. 0 is the default.
Extend to 1.0 Pickup: 1 to extrapolate overcurrent relay curves to 1.0 times pickup; 0 otherwise. 0 is the default.
Ignore Phase Shift: 1 to ignore phase shift of transformers and phase shifters; 0 otherwise. 0 is the default.
Ignore MOVs: 1 to ignore MOVs that protect series capacitors. 0 otherwise. 1 is the default.
Generator I Limits: 0 to ignore all generator current limits. 1 to enforce current limits A, and 2 for current limit B. 0 is the default.
5. Size Information (optional)
The size information lets the program know, at the very beginning of the file, how many objects of different kinds are in the file. This information enables the program to allocation the memory for these objects just once, instead of doing it piecemeal as data are read in. This has the effect of speeding up the reading of large files, sometimes by as much as a factor of 10. The size information includes one or more of the following, on separate lines:
'NObus= ': Total number of buses
‘NOgen=’: Total number of generators
‘NOload=’: Total number of loads
‘NOcap=’: Total number of shunts
‘NOline=’: Total number of transmission lines
‘NOxfmr=’: Total number of 2-winding transformers
The object counts need not be exact. The program will automatically reallocate more memory if the count is less than the actual number of objects.
An example system-parameters section is shown below.
[SYSTEM PARAMETERS]
mva= 100
switchX= 0.001
switchR= 0
lineB= 0
ignoreShift= 0
genZType= 0
pf= 20 1 1 20 20 6
sc= 0 0 0 0 0 0 0 1 0
NObus= 31
NOgen= 6
NOload= 1
NOline= 36
NOxfmr= 4