Setting Program Options

Most PSS/E calculation and reporting functions recognize one or more program settings. When PSS/E is installed on the system, default PSS/E program settings are established. You may modify a given program setting during a PSS/E work session by selecting the Misc>Change program set-tings (OPTN)... option. The Program Setset-tings dialog is displayed in Figure 1-11.

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Users Manual Starting the PSS/E Application

Figure 1-11. Program Settings Dialog

Bus Input: Buses are selected in the interactive dialog portions of PSS/E by either bus number ("Number" option) or extended bus name ("Extended Name" option). Extended bus names consist of the twelve-character alphanumeric name plus the bus base voltage.

Bus Output: Buses are ordered in PSS/E reports in either ascending bus number order ("Number" option) or alphabetical extended bus name order ("Extended Name" option).

Power Output: Power output may be output in units of either MVA or kVA.

Voltage Output: Voltages are tabulated in either per unit (pu) or kV.

Voltage Input: Voltages are reported and input in either per unit (pu) or kV.

Transmission Line Units: Transmission line (not transformer or generator) impedances input and/or output in either per unit (pu) or ohms; line capacitances are in either per unit or microfarads.

Short Circuit Units: Fault analysis results are tabulated in either physical units or per unit (pu).

Short Circuit Coordinates: Fault analysis results are tabulated in either rectangular (e.g., MW, Mvar) or polar coordinates (e.g., MVA, pf).

Short Circuit Phase Modelling: Fault analysis calculations handle either three-phase sys-tems (3-Phase) modeled by their positive, negative, and zero sequence networks, or two-phase systems (2-Phase) used in some electric traction systems modeled by their positive and zero sequence networks.

Default Rating Set: Default branch rating used in power flow output and contingency anal-yses. Selections can be Rate A, Rate B, or Rate C.

Starting the PSS/E Application Users Manual

Tap Adjustment: Sets the mode of tap adjustment in the solution process to be either Off, Step, or Direct.

• The Off mode suppresses transformer adjustments during the power flow solution.

• In the Step mode of tap adjustment each transformer is checked independently outside of the main power flow iteration. If the controlled voltage is outside of its specified band the tap ratio is moved at least one user-specified step.

• The Direct mode is a Newton-based method of tap adjustment. If any tap ratios need to be adjusted, a simultaneous adjustment is made of all voltage controlling transformers as well as all Mvar controlling transformers and all bus voltage mag-nitudes. Upon convergence of the main power flow iteration, tap ratios of control-ling transformers are moved to their nearest step and the solution refined with tap ratios locked at those positions.

Area Interchange: Sets the mode of area interchange control.

• Disabled indicates to disable area interchange control.

• If Tie lines only is selected, an area’s net interchange is defined as the sum of the flows on all of its tie lines; a tie line is a branch (ac line, dc line, or series FACTS device) connected to a bus residing in the area whose other end is connected to a bus that is not in the area. Tie flows are calculated at the metered end as power flowing out of the area.

• If Tie lines and loads is selected, a load whose area assignment differs from that of the bus to which it is connected is considered a tie branch for net interchange calculation purposes; that is, an area’s net interchange includes tie line flows as well as contributions from loads connected to area buses that are assigned to areas other than the bus’ area, and from loads assigned to the area which are con-nected to buses assigned to other areas.

File Overwrite Option: If asked to save to a file that already exists, PSS/E may either auto-matically overwrite the file or ask the user before doing so.

Startup Bus Dimensions: Shows the current size level of PSS/E in terms of the maximum number of buses allowed. A new bus size level may be specified and will take effect when the program is restarted, assuming the Save options to file box is checked. This setting may be overridden by the user at the time PSS/E is initiated by specifying the "-buses" com-mand line token followed by the desired bus dimension as described in Section 1.7.1.

Newton Solution Tolerance: The Newton Solution convergence tolerance (MW/Mvar) is set to this value when a Newton Raphson solution is selected in PSS/E. This is the toler-ance used to determine when the power flow has established convergence.

Base Frequency: The base or system frequency in Hertz (commonly 50 or 60 Hz).

Matrix Growth Factor: The matrix growth factor used in allocating working arrays by activ-ities involving the ordering, factorization, or triangularization of network matrices. PSS/E updates this value as required, so that users do not normally need to be concerned with it.

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Users Manual Overview: Files Used by PSS/E

power flow solution activities and in the interchange subroutines accessible from IPLAN programs.

Report line shunts: Line shunt powers may optionally be reported in power flow output activities.

Enable fault analysis warnings: Certain warning messages can be either printed or sup-pressed in the fault analysis input and solution activities (i.e., missing generator data and sequence network isolated buses).

Setup fault network before solving with unbalances: Allows or suppresses automatic set-up of the factored matrix working file prior to running unbalanced fault analysis.

Adjust phase shift: Turns phase shift adjustment ON or OFF during the solution process.

Adjust DC taps: Locks or unlocks dc transformer taps during the solution process.

Switched shunt adjustments: Allows or suppresses the adjustment of switched shunts during the solution process.

Non-divergent Newton solution: Allows the voltage vector of diverging power flow itera-tions to be captured and the power flow solution to be terminated prior to blowing up when performing the fixed slope decoupled Newton-Raphson solution (FDNS), fully coupled Newton-Raphson solution (FNSL) or AC contingency analysis (See Section 4.3.9.6).

Save options to file: Checking this box saves the options settings to a binary file psse.opt.

The file is saved in the current working directory, the location where the program was last invoked. This file must remain in the working directory, otherwise, the options will not be preserved. There is no default psse.opt file provided with the program installation. This file is created only when this option is checked.

If this option is not selected (checked), startup bus dimensions and other options will not be preserved.