ZLF.EXE
Revision 1.0
June 2022
Norbert Doerry
SYNTAX: zlf.exe file.xml -ooutputfile.csv -d
where
file.xml = input .xml file
outputfile.csv = output (results) file in .csv format
-d = debug mode (optional)
if the outputfile.csv is not specified with the -o option, output is printed to stdout (normally screen)
INTRODUCTION
zlf calculates zonal load factors and zonal total operating loads as defined in DDS (now DPC) 310-1 Rev 1:
"Electric Power Load Analysis (EPLA) For Surface Ships" (Naval Sea Systems Command).
As stated in DDS 310-1, "Zonal load factors account for increased variability in load due
to having fewer loads than for the total ship. Zonal load factor analysis is an extenstion of
the load factor analysis method to zonal power system elements."
The use of the zonal load factor method is recommended for any power system apparatus providing
power to more than two loads except for power generation at the total ship level. The load factor
method determines the average electric load and is suitable for determining the required rating of
generators and for calculating annual fuel consumption and endurance fuel consumption. The zonal
load factor method will in general result in a higher load that reflects an estimate of the peak load
the power system apparatus is likely to experience. The zonal load factor method is useful for determining
the rating of power system apparatus, but should not be used for annual fuel consumption and
endurance fuel consuption calculations. In particular, since power electronic conversion equipment
typically will current limit when overloaded, the use of the zonal load factor method will help avoid
overloading these devices.
APPLICATION NOTES
If a load has a load factor of 0, zlf assumes the load is turned off and it does not participate in
the zonal load factor calculations. A load that may be employed in a given operational condition and
ambient condition, but is rarely on should be given a very small load factor (0.01 for example) so that
it participates in the zonal load factor calculations. In particular, its residual power may be the
largest of the loads and thus may be used in the zonal total operating load calculations.
zlf does not apply margins and service life allowances. These should be applied to the zonal total
operating load to obtain the zonal demand power. The power system apparatus should have a power rating
no less than the zonal demand power.
If a zonal power apparatus is in turn a load to another zonal power apparatus, recommend using the zonal
total operating load (plus any associated losses within the zonal power apparatus) for the peak load of
the apparatus serving as a load.
COPYRIGHT NOTICE
Copyright (C) 2022 Norbert H. Doerry
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
if you find any bugs in this software, please email doerry@aol.com
INPUT FILE FORMAT
The input file uses an XML structure ...
this text is ignored by the program.
Switchboard 1a
Any number of operational_conditions and ambient_conditions may be defined.
The names specified below must be used exactly when defining load factors
to calculate zonal loads for
Emergency
Cruising
Functional
to calculate zonal loads for
summer
spring_fall
winter
lighting Fixtures - Machinery Spaces
332 Ship Weight Breakdown Structue number -- used for identification of load
25 in kw - nameplate rating of equipment
1.0 = peak load / connected load
.9 oc = operational_conditon (must be one defined above)
.9 ac = ambient_condition (must be one defined above)
.9 lf = load factor = average load / connected load
.9
.9
.9
.9
.9
0.9
.99 Power Factor (positive is inductive / lagging negative is capacitive / leading)
power factor is not currently used.
lighting Fixtures - Outside Machinery Spaces
332
25 in kw
1.0
.4
.4
.4
.6
.6
.6
.6
.6
0.6
.99
Any number of loads may be defined. A load factor need not be defined for every combination of operational
condition and ambient condition.
OUTPUT FILE FORMAT
The output file is a .csv file that can be imported into Microsof EXCEL or other spreadsheet programs ....
"zlf","Version","1.0","Jun 26 2022"
"Switchboard 1a"
"zlftest01.xml"
"zlftest01.csv"
"Operational_Condition","Cruising"
"Ambient_Condition","summer"
"Total_Connected_Load_KW",770.000000
"Total_Load_Factor_Load_KW",347.500000
"Zonal_Total_Operating_Load_KW",495.017986
"Total_lf",0.451299
"Total_zlf",0.642881
"SWBS","514","Chill Water Plant","Connected_Load_KW",300.000000,"Peak_fraction",0.900000,"LF",0.700000,210.000000,"ZLF",0.855396,256.618705
"SWBS","512","Duct Heaters","Connected_Load_KW",220.000000,"Peak_fraction",0.900000,"LF",0.000000,0.000000,"ZLF",0.000000,0.000000
"SWBS","450","Radar","Connected_Load_KW",200.000000,"Peak_fraction",1.000000,"LF",0.500000,100.000000,"ZLF",0.787770,157.553957
"SWBS","332","lighting Fixtures - Outside Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.600000,15.000000,"ZLF",0.628777,15.719424
"SWBS","332","lighting Fixtures - Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.900000,22.500000,"ZLF",0.907194,22.679856
"Operational_Condition","Cruising"
"Ambient_Condition","spring_fall"
"Total_Connected_Load_KW",770.000000
"Total_Load_Factor_Load_KW",405.500000
"Zonal_Total_Operating_Load_KW",625.518496
"Total_lf",0.526623
"Total_zlf",0.812362
"SWBS","514","Chill Water Plant","Connected_Load_KW",300.000000,"Peak_fraction",0.900000,"LF",0.600000,180.000000,"ZLF",0.799753,239.926017
"SWBS","512","Duct Heaters","Connected_Load_KW",220.000000,"Peak_fraction",0.900000,"LF",0.400000,88.000000,"ZLF",0.644143,141.711467
"SWBS","450","Radar","Connected_Load_KW",200.000000,"Peak_fraction",1.000000,"LF",0.500000,100.000000,"ZLF",0.746609,149.321825
"SWBS","332","lighting Fixtures - Outside Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.600000,15.000000,"ZLF",0.624661,15.616523
"SWBS","332","lighting Fixtures - Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.900000,22.500000,"ZLF",0.906165,22.654131
"Operational_Condition","Cruising"
"Ambient_Condition","winter"
"Total_Connected_Load_KW",770.000000
"Total_Load_Factor_Load_KW",485.500000
"Zonal_Total_Operating_Load_KW",652.878991
"Total_lf",0.630519
"Total_zlf",0.847895
"SWBS","514","Chill Water Plant","Connected_Load_KW",300.000000,"Peak_fraction",0.900000,"LF",0.500000,150.000000,"ZLF",0.722451,216.735324
"SWBS","512","Duct Heaters","Connected_Load_KW",220.000000,"Peak_fraction",0.900000,"LF",0.900000,198.000000,"ZLF",0.900000,198.000000
"SWBS","450","Radar","Connected_Load_KW",200.000000,"Peak_fraction",1.000000,"LF",0.500000,100.000000,"ZLF",0.705973,141.194645
"SWBS","332","lighting Fixtures - Outside Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.600000,15.000000,"ZLF",0.620597,15.514933
"SWBS","332","lighting Fixtures - Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.900000,22.500000,"ZLF",0.905149,22.628733
"Operational_Condition","Functional"
"Ambient_Condition","summer"
"Total_Connected_Load_KW",770.000000
"Total_Load_Factor_Load_KW",387.500000
"Zonal_Total_Operating_Load_KW",490.112903
"Total_lf",0.503247
"Total_zlf",0.636510
"SWBS","514","Chill Water Plant","Connected_Load_KW",300.000000,"Peak_fraction",0.900000,"LF",0.700000,210.000000,"ZLF",0.839355,251.806452
"SWBS","512","Duct Heaters","Connected_Load_KW",220.000000,"Peak_fraction",0.900000,"LF",0.000000,0.000000,"ZLF",0.000000,0.000000
"SWBS","450","Radar","Connected_Load_KW",200.000000,"Peak_fraction",1.000000,"LF",0.700000,140.000000,"ZLF",0.854839,170.967742
"SWBS","332","lighting Fixtures - Outside Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.600000,15.000000,"ZLF",0.625806,15.645161
"SWBS","332","lighting Fixtures - Machinery Spaces","Connected_Load_KW",25.000000,"Peak_fraction",1.000000,"LF",0.900000,22.500000,"ZLF",0.906452,22.661290
... The above sections are repeated for every combination of Operational_Condition and Ambient_Condition.