PLS CADD

[ekieder]

Hello

I´ve just started to work with PLS CADD, I´m having a little bit of trouble, and I´d be really grateful if someone could give me a hand.
I have got cartography, towers´ models, described extra-cost & prohibited zones and already defined criteria
and now I´m trying to use Optimum Spotting. We are simulating a double circuit line but when I run simulation
I can just get a simple circuit, no fibre line and no grounding cable.
What am I doing wrong? Because to simulate optimum spotting assigning differents towers it has got to take into
account 2 circuit and fibre´s forces. Hasn´t it?


Thanks a lot

 

[transmissiontowers]

I'm a structural guy and we don't use optimum spotting but from the demo I saw a few years ago the O.S. algorithm only looks at ground clearance over the terrain and does the spotting to find the lowest cost for a line. I don't believe it takes the strength of the towers into account when doing O.S. The towers have a wind and weight span specified and the program picks the cheapest set of towers that make up the line. The program only needs 1 ckt to check the spotting because it is only looking at the sag of the lowest wire. After the O.S. is done, then you string wires, fiber, OGW and check the strength of the towers.

You can get much more detailed answers by calling PLS Tech support. You should also think about signing up for the PLS-CADD line design course.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Thank you very much "transmissiontowers", I thought maybe using PLS Tower I could generate a simplified model
to be used by the Optimum Spotting.
So after selecting the possible structures and once I´ve simulated them with one single conductor
(what would it happen if terrain has got and slope?), I have got to string the other wires and calculate strengths.
If an structure does not fit, I set manually another on its place.

I´ll follow your advice and I´ll contact PLS Tech Support. Regarding the PLS-CADD line design I´d like to
deepen a little bit more before, in order to make the most of it.

Thanks a lot

 

[transmissiontowers]

From my experience, there is a lot to learn about the software. If you have a senior engineer around that has experience with the software and the optimum spotting, lean on their experience. The manual is fairly good and it would be good to get a basic understanding by reading the manual and opening the example line models and see how the O.S. works.

From my meager understanding, you start with a route you have terrain data for. You identify the hard angle points where the line turns, then you identify a set of possible candidate structures with their capacities in wind and weight spans plus the max angle. You then run O.S. and it picks a set of towers or poles based on the cheapest line design. I believe it assumes that the tower/pole will be strong enough based on the simple parameters you input. You then string all your wires and do the structural analysis to make sure the towers are indeed strong enough. Now, if the selected tower is not strong enough and you have to replace it with a slightly taller one, then you need to re-run the O.S. with the new tower's weight and wind span parameters because the spans could change with the new O.S. run.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[transmissiontowers]

Check out the tech notes section on the PLS web site to see some help with spotting.

http://www.powline.com/products/optimization.html

There is a new video "Introduction to the QuickSearch Toolbar" (

http://youtu.be/DwYgf5e9lOk)

that may also be helpful.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Thank you very much "transmissiontowers". I am following your advise and I continue visiting Power Line´s webpage with its interesting technical documents in order to emerge victorious from my personal "battle" against the manual . PLS Tech support also answer quite quickly my concerns about Optimum Spotting.
You were right, as it takes into account just the lowest conductor.
For a double circuit line I proposed this procedure:
1)Optimum Spotting with simple circuit line
2)String the other circuit and fibre cable
3)Run calculations
4)Manually change inappropiate structures

You proposed also 5) re-running Optimum Spotting


Thanks a lot

 

[transmissiontowers]

Unless you are running a line along the side of a hill or mountain the center-line of the alignment should be fine. I'm assuming that the double circuit is 2 circuits vertical on 2 sides of the tower or poles on a side hill, one of the circuits is closer to the ground. I'm not sure if O.S. takes conductor blowout into consideration when it spots structures. You could need a taller extension to keep the wire from getting too close to the side hill as it is displaced by wind.

You would re-run O.S. if you changed the wire height by swapping out a taller/stronger tower. It is fairly easy to get into analysis paralysis from trying to save the last $0.01 on a T-Line project. You have to say close enough at some point and add a 5' clearance buffer to take care of unknowns.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Hi "Transmissiontowers" and thanks a lot for your help.
I am following the procedure we commented previously, but when I run
Optimum Spotting sometimes it strings the line on zig zag, connecting the left cross
of a post with the right one of the following. I don´t know if it´s a common error
that has to be corrected manually or if I did something wrong.

I ´ve got another problem when I press authomatic sagging it lets to choose a cable or wire, and if a choose
the same high voltage to form the double circuit it strings not just 3 phases but 2 more using the attachment for OPGW.

Thank you very much

 

[transmissiontowers]

The program tries to figure out which wires to string and I think it tries to connect like numbered sets or like named sets. This numbering and naming comes from the structure files under the PLS-CADD Insulator link. When you gave it the list of structures you should have named and numbered the conductor sets with some consistency. For instance, name the lower left attachment set the same on all the structures and the lower right set a different set and name.

When the program automatically strung the wires on your line, I'll bet it connected all the 1:1's together and they may have been on opposite sides of the tower.

The autosag just pulls the wire up to tension based on the parameters you set in the criteria file. As far as I know the autosag does not string more wire, it just pulls the wires already there up to tension.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Thanks a lot for your help

I have got another question, as I am running PLS CADD for a non specified rule.
I think I didn´t understand well the way of using PLS Tower with PLS CADD.
With PLS CADD we obtain a model of how the forces affect towers.
So imagine I have to run for example EN 50341-3-16 for Norway
I would have to modelise all towers applying all different force cases contained
in the rule. After having modelised all cases I ´d obtain a model to use in PLS CADD.
In what does it consist? Does it give some short of limits? Or does it interact with metheorogical data?

Regarding the cable criteria, which percentage of ultimate do I have to set (Every Day Stress / defined criteria p.e. 30%)?



Thanks again

 

[transmissiontowers]

The PLS-CADD guys have several European codes to select from in the criteria file. For your T-Line in Norway, you (or your utility client) will have to develop a Criteria File for that country and you get to decide what weather loads to apply to the line. The criteria file also determines the loads applied to the towers or poles. The cable tension percent is also set in the criteria file. Once you have a Criteria established, you will need lattice tower models for the line. The utility may have them already done or you will have to model them yourself. Once you have the towers and cable pulled in, you can then start checking the structures to see if they are strong enough.

Now, if all you care about is the ground clearance, you can skip the structure models and input stick figures that represent the attachment points so you can check ground clearances when the wire heats up under electrical load.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Hi Transmission Towers thanks a lot for the help
So if I have got the .m2 file Can I simulate the line for any weather case?
I mean, if in Norway per example they use finnish towers and I have got their .m2 files.
Can I run Optimum Spotting with those .m2 files, once I have defined the Criteria in PLSCADD
for Norway? Or I should create another .m2 file using norwegian rule?

Tahnk you again

 

[transmissiontowers]

I'm not sure what a .M2 file is as we don't use Optimum Spotting but I guess it might be Method 2 models which define the wind and weight span of a structure. In that case the .m2 models should just define the capacity of the towers and you will develop the Criteria File for Norway and let O.S. spot the structures for you.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Thanks a lot Transmission Towers akwardly I erased some mails
and I didn´t notice your answer.
I am going to contact the PLS Tech support in order to have more information
about .m2 files



Thank you again

 

[ekieder]

Hi Transmission Towers

PLS Tech Support ansewered me taht I ´ve to create new .m2 files as weather conditions changed and therefore loads too.
Now my problem is finding the way to export climate casesfrom PLSCADD to PLS Tower.
I am not sure either whether I have to generate a .lca file or a .lic one.

Thanks a lot

 

[transmissiontowers]

The export of the loads and weather condition from PLS-CADD to Tower (or Pole) is automatic. All you need to do is Edit the Tower from PLS-CADD and the structure opens with the loads already applied. At that point you run the model and find out how many members are overloaded. I don't use the .LIC file much and I think it is a unit load per foot or meter of cable and this may be what you need for the Opt Spotting.

You can generate a LCA file (or a LIC file) from PLS-CADD and then open Tower and open that LCA file, but it is much easier to let the program do the transfer for you.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Hi TransmissionTowers

First of all, thank you for your answer.
I don´t understand the way to carry out the simulation.
After opening a .tow file in PLSCADD by using Structure->Structure Edit
I get to PLSTower but when I go to Loads it ask me to load a .lca file.
If I open a .m2 file I can just modify the ways phases are set, insulators,
but I have no trace of weather or the conductors.
If I directly open .m2 in PLS Tower I can modify weather conditions but I haven´t
got a clue of how I can insert wires and fiber.


Thanks a lot

 

[transmissiontowers]

I guess I don't understand the .M2 files and how they fit into the line design concept. You probably need to read the PLS Manual about Method 1, Method 2, and Method 3 structures and spotting. If you create a line model using Method 4 structures, then string wire, you will see that when you edit the structure, the loads are transferred to the structure model and you can run the model and find out if members are overloaded.

As I understand the line design and Opt. Spotting, you define Method 1 structures that have a wind and weight span allowable and the program creates a line. After that you replace the Method 1 structures with the Method 4 structures and do the structure check.

_____________________________________
I have been called "A storehouse of worthless information" many times.

 

[ekieder]

Thanks again for your answer Tranmission Towers.
I have reached the point to generate .lic files and therefore
to modify .m2 files. To do that I draw some towers and string the wires
and fiber, once that was done I defined all criteria including Structure Loads
(Method 3,4). But I don´t understand why I´ve got to define information for Methods
3 & 4 if Optimum Spotting runs on Method 1 or 2.

Thanks a lot

 

[transmissiontowers]

You have reached the ends of my knowledge on PLS-CADD and the O.S. functions. You probably need to call or eMail PLS Tech Support for a better explanation if reading their manual does not get you past the rough part you are stuck in now.

_____________________________________
I have been called "A storehouse of worthless information" many times.