There are two types of miscellaneous data cards: floating-point and integer. Both card types will be explained in the remainder of section II-B.
Further, there are also extensions to these miscellaneous data cards. These extensions will be explained in section II-C.
floating-point miscellaneous data card
The first non-comment card that is not recognized as being any of the preceding special-request cards will be assumed to be the floating-point miscellaneous data card, which has the following format:
2345678901234567890123456789012345678901234567890123456789012345678901234567890
1 2 3 4 5 6 7 8
1
E8.0 E8.0 E8.0 E8.0 E8.0 E8.0
DELTAT TMAX XOPT COPT EPSILN TOLMAT
E8.0
TSTART
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Parameters:
DELTAT : the size of the time step of the numerical integration, in seconds. A simulation will be calculated at discrete moments of time that have this time separation. Take care of the Nyquist criterion: the time step preferably should be 1/2 ... 1/10 of the smallest time constant of the system one wants to simulate. Whenever nonlinear elements are present in the network under study, an even smaller time step might be advisable.
TMAX : the end time of the study, in seconds.
XOPT : a value that indicates whether it is inductance in millihenries or inductive reactance in ohms that is to be keyed on linear branch cards.
1) If XOPT = 0, inductances are to be keyed in millihenries.
2) If XOPT > 0, then values are to be in ohms at frequency XOPT (in Hertz). In either case, remember that this choice of the miscellaneous data card can be changed at any point of data input by means of the first argument of a $UNITS card.
COPT : a value that indicates whether it is capacitance in microfarads or capacitive reactance in micromhos that is to be keyed on linear branch cards.
1) If COPT = 0, capicitances are to be keyed in microfarads.
2) If COPT > 0, then values are to be in micromhos at frequency COPT (in Hertz). In either case, remember that this choice of the miscellaneous
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data card can be changed at any point of data input by means of the second parameter of a $UNITS card.
EPSILN : the near-zero tolerance that is used to test singularity of the real coefficient matrix within the time-step loop. A blank or zero value means that the value of the STARTUP file will be used. For 64-bit (REAL*8) computation which is the most common, a default value of 1.E-8 is typical.
Historically, work began using 36-bit computation, for which a default value of 1.E-5 was used.
TOLMAT : the near-zero tolerance that is used to test singularity of the complex admittance matrix [Y] of the steady-state, phasor solution. A blank or zero value means that a value equal to that of EPSILN will be used. Please note that TOLMAT can NOT be specified in the STARTUP file.
TSTART : The beginning time of a simulation, in seconds. Normally, TSTART will be zero or blank. Only when the "START AGAIN" feature is in use (see section II-A-33), it can be usefull to specify TSTART > 0 (e.g. put the value equal to TMAX of a previous data case you want to continue). Details regarding final table dumping, etc. can be found in DC49.
integer miscellaneous data card
The just-described floating-point miscellaneous data card is to be followed by an integer miscellaneous data card bearing the following information:
2345678901234567890123456789012345678901234567890123456789012345678901234567890
IOUT gives the frequency of LUNIT6 (printed) output within the time-step loop. E.g., a value of 3 means that every 3rd time step will be printed.
A value of zero or blank is changed to unity. For "FREQUENCY SCAN" usage, it is output within the loop over frequencies that is controlled, rather than the loop over time, of course.
IPLOT gives the frequency for saving solution points of the time-step loop for purposes of later plotting. E.g., a value of 3 means that every 3rd time step will be saved. A value of zero or blank is changed to unity, and any even value is increased by one to make it odd. An even plotting frequency is not allowed because of the likelihood of deception: a saw-toothed oscillation would go unnoticed.
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IDOUBL controls the LUNIT6 output of a table showing network connectivity.
A value of zero or blank will suppress such output, whereas unity will produce it. For each node there is shown a list of other nodes to which there are physical connections. Mutual coupling between phases of multiphase elements is ignored in this output, as is the capacitance to ground of Pi-circuits and distributed-parameter lines. The name "TERRA "
(as read in from the STARTUP file) is used for ground instead of six blank characters, to improve readability. Ordering of the rows is in order of input, except for the final row, which applies to ground (node number one, which is labeled "TERRA FIRMA").
KSSOUT controls the printout of the steady-state phasor solution. There are 3 basic types of outputs: branch flows, switch flows, and nodal injections. These can be controlled by the value of KSSOUT as follows:
0 ===> No steady-state solution printout.
1 ===> Print the complete steady-state solution: branch flows, switch flows, and source injections.
2 ===> Print switch flows and source injections, but not branch flows.
3 ===> Print branch flows requested by column 80 punches, switch flows, and source injections.
MAXOUT controls printout of extrema at the completion of the simulation.
Keying a zero or blank will suppress such computation and output, whereas the value unity will produce it.
IPUN is used to request the input of an extra, following card to vary the printout frequency. Use a value of "-1" to request such an extra card, or zero or blank if no such extra card is wanted. Refer to Section II-C-4 for details of the following card. Alternatively, use "CHANGE PRINTOUT FREQUENCY" of Section II-A to accomplish the same thing.
MEMSAV controls the dumping of EMTP memory onto disk at the end of the simulation for subsequent use with the "START AGAIN" request of Section II-A. Key "1" if such memory saving is desired, or zero or blank if it is not. For the single, deterministic simulation, the table saving is done at time TMAX (floating-point miscellaneous data parameter). For Monte Carlo ("STATISTICS") studies, this is upon completion of energization number NENERG (integer miscellaneous data parameter). Memory saving is a powerful and useful tool of the production user. However, be warned that such table saving and later use may be computer dependent, so information about the computer being used should be consulted. The name of the resultant tables is determined by a $OPEN declaration on LUNIT2 that must precede such usage. Most commonly the $OPEN is placed immediately before the blank card ending output requests. Also, once the tables are complete, it is the user's responsibility to disconnect them (use $CLOSE at the beginning of following plot cards). Any user of this feature should be further warned that a later awakening of the hibernating simulation is guaranteed only if the same program version is saved and is used for the following "START AGAIN" simulation. For an illustration involving a single, deterministic simulation, see BENCHMARK DC-32 and DC-49. For such usage with a Monte Carlo study, see BENCHMARK DC-24 and DC-40.
A final comment is about Monte Carlo studies. If some study is to be solved in two or more independent pieces that are later to be combined,
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then for the 2nd or later portion (each associated with a "LOAD MORE SHOTS" declaration of the execution that combines the results), the value
"2" is to be keyed rather than "1". The difference is great. Unity results in the dumping of all tables (including LTLABL words of "LABCOM"), whereas "2" will produce an abbreviated file consisting of only switching times and extrema. An abbreviated file is useless by itself, but can be appended to a complete file by means of the "LOAD MORE SHOTS"
declaration. Of course, it is important to have a different seed for the random number generator of such simulations that are later to be combined, since otherwise, the user would just be repeating the same energizations (a waste of computation). For an illustration involving Monte Carlo simulations, see BENCHMARK DC-24 and DC-40.
ICAT is to be left blank (or zero) if there is to be no permanent saving of raw plot data points that might be written to I/O channel number LUNIT4 during the simulation. But should such permanent saving be desired, then a positive value is required:
1 ===> Save the points, but ignore any batch-mode plot cards that might be present.
2 ===> Save the points, and also honor any batch-mode plot cards that might be present.
For most computers, the disk file in question will be internally named based on the date and time of day when the simulation began. See the plot file heading for such details. Such details are controlled by installation-dependent SUBROUTINE SYSDEP, so it is not possible to be much more specific. See details for the computer of interest.
NENERG is to be left blank (or zero) for single, deterministic simulations. But for "STATISTICS" or "SYSTEMATIC" data cases, this is to be the total number of energizations (exclusive of any possible, extra, base-case solution). Append a minus sign if "SYSTEMATIC" usage is involved --- a flag to distinguish such a case from Monte Carlo studies. Also, remember that an extra "STATISTICS" or "SYSTEMATIC" miscellaneous data card (Section II-C-1) must follow.
IPRSUP is normally left blank or zero. If keyed as a positive value, this is the diagnostic printout control that is to be applied to all UTPF overlays. The same result can be obtained via parameter IPRSUP in the STARTUP file. But since the user normally will want to selectively control such output overlay by overlay, he should instead use the "DIAGNOSTIC"
special-request card (see section II-A-12).
Interpretation of the just-described floating-point and integer miscellaneous data cards confirms only the first three floating-point parameters, but all integer parameters. As an illustration, consider the two associated output lines of BENCHMARK DC-4:
C 1 2 3 4 5 6 7
C 34567890123456789012345678901234567890123456789012345678901234567890123456 C ---|--- Misc. data. 1.000E-02 6.000E+00 0.000E+00 | .010 6.0 Misc. data. 1 1 1 1 1 -1 0 0 0 0 | 1 1 1
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