GeneralDynamicsLoad FlowPowerflow DataPrintingExtended Records |
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How do I set up Textpad 4.1 for use with PSLF EPCLs? Refer to the documents below for details: This file may not have been installed with Textpad 4.1. It should be placed in c:\Program Files\Text Pad 4\samples\epcl.SYN. |
| How do I get smaller characters on a one-line diagram? To change the size of the characters on a one-line diagram, select PARM; then select DIS (display parameters). To reduce the font size temporarily, reduce the value in the Char. Height field and press Enter. To change the font size permanently, reduce the value on the line labeled olgrpar[0].charsize. For further information, see manual sections olgr, gedi and parm. |
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How do I perform a dynamic simulation? You can perform a dynamic simulation interactively or through EPCL: |
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How do I import dynamic data from a different format? PSLF software can import dynamic data in WSCC and PTI formats. WSCC data is imported using rdws. Under the small menu, rdws is in the PSDS panel. Using the large menu, it is under dsix. |
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What do I do if my dynamic case will not initialize? PSLF displays error messages if any in-service generators do not have dynamic models. You must correct these problems before running dynamic simulations. |
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How do I resolve unsteady initial conditions in models? After initializing, PSLF prints a message indicating the number of models with unsteady initial conditions. The program checks all state variable derivatives against a default tolerance of 0.001. This is a very tight tolerance, and it is very common to see a message that several hundred models initialized with unsteady initial conditions. To determine which models have unsteady conditions and the magnitude of the errors, run the EPCL program usteady.p. Note that you must have an epslf subdirectory under your working directory to use this program. This program lists all models with derivatives greater than a specified tolerance. Check these models for bad data (such as bad limits or an incorrect MVA base) and initial operating conditions (such as a very high terminal voltage or generation above rating) in the powerflow. |
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My system does not produce flat lines during a no-disturbance simulation. How do I track the problem? First, follow the directions above to check for bad data or initial conditions. If you do not find the problem, using PLOT may help. We recommend that you run the standard EPCL program modstat.p to turn off all models whose generator status is zero before initialization; then initialize and run out to one second or more. Follow these steps to identify the machines causing problems: 1. From the PSLF application, access plot. 2. Go to view and filter out all machine angles (F1, “ang”, F4 under the type column). 3. Tab over to the Spread column and sort backward (F11). 4. Look for the machines with the largest spreads in angle, and plot them using the F8 key, geti or plot. 5. Perform the same search for terminal voltage (“vt”) and field voltage (“efd”). 6. Return to Dynamics and check the data for the models with the largest spreads. Note: If you need to change data, you must get the base powerflow and re-read the dynamic file first. |
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What is the difference between a bus fault and a line fault, and how do I simulate them? Bus and line faults are specified using the run panel or using the dypar records in EPCL. The bus fault applies a fault at a bus and requires you to perform all switching actions to clear the fault. The line fault can apply a fault at any point along a transmission line, and clears the fault by tripping the line. |
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What is the difference between Mbase and MbaseR? The Mbase value in the model edit tables represents the gens.mbase value. This is the same as the data listed in the powerflow edit table under gens. This value represents the Mva base of the machine as represented in the powerflow data. MbaseR is the Mva base of the individual rotor represented by the dynamic machine model, and is the base for the machine dynamic parameters. |
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What is Mwcap used for? Mwcap specifies the total turbine MW capability. All per-unit parameters in the turbine/governor models are specified on this base. |
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What do I do if my load flow does not solve because of bouncing taps? In the EDIT:TAP table, ensure the upper and lower limits are integral steps. In other words, tmax minus tmin, divided by step, is a whole number. If the values are not integral steps, adjust the limits or run the EPCL program tapon.p. |
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How do I set up a three winding transformer? A three winding transformer requires four buses in the database: the from bus, the to bus, the tertiary bus and an internal bus. After you add the buses to the database, you can add the transformer to the EDIT:TRAN table using the F6 key. It is always best to replicate an existing transformer. Use the F8 key (record editor) to verify or modify each data entry. Make sure the following data are entered: • From bus • To bus • Unit ID • Trans status • Tap control type • Reg bus • Tert bus • 3wpt (internal) bus • Base • X from-to, X from-tert and X tert-to • From/To/Tert wind nom volt • TCUL tap • From/To/Tert fixed tap (if this is a TCUL, enter the Max/Min TCUL ratio, Max/Min Cont voltage and TCUL step) |
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Why does my case diverge when calculating short circuit currents? Check the SCSC:EDIT:GEN table for zero values of X1, X2 or MBASE. |
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What are QRF and PRF in the generator table? For multiple generators regulating the same bus, this is the fraction of the total MVAR (QRF) or the total MW (PRF) to be served from the individual generator. For example, if generator 1 is 80 MVAR and generator 2 is 20 MVAR: • The QRF factor is 80÷(20+80) = 0.8 for generator 1 • The QRF factor is 20÷(20+80) = 0.2 for generator 2 If you enter a value of 1 for QRF, the PSLF software automatically adds the individual factors to obtain the total. If three units have a QRF of 1, each generator contributes 1/3 or 0.333 to the total MVAR. The PRF is used only for area interchange MW adjustment. |
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What does zero diagonal mean as a solution error? There is a regulation conflict with generators and/or SVDs. To resolve the conflict, follow these steps: 1. Note the node (external bus number). 2. Use the SCAN command on that bus number. 3. Click the white box on the bus, and select LIST from the menu. Result: The startup window opens, showing all attributes for the selected bus including lines connected and buses regulated by the selected bus. Either rectify the conflicts or self-regulate existing generators or SVDs. |
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How do I import powerflow data from other formats? You can import powerflow data from other formats such as WSCC or PTI. Note that the data you are importing must be in ASCII format, not a binary history file. |
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How do I use extended records? The purpose of extended records is to add new data fields to the PSLF database. You can add new members to the existing records or create complete new records. The most common use is to create complete new records. |
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How do I build my own edit table? You can view and change a record that was added with the extended record option: |
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