Does any Electrical Power Engineers use PLS-CADD or it is just a Structural Engineers' tool? 3

[engratcorner]

Hello all,

I have been using PLS-CADD on electric distribution systems for 7 months. It's been like a structural engineering tool for me but I end up in building something more of electric distribution system. I wonder does PLS-CADD have any electrical engineering side of it or are there any electrical engineers they use PLS-CADD in the world! - might be an awkward question but I'd like to know if there is any electrical side of this huge software.

Thank you,

 

[bacon4life]

Our entire line engineering department consists of EEs. They do detailed design of all wood structures under 100 ft. For steel structures under 100ft, our line department works with either in house civil engineers or civil engineering consultants for the detailed pole designs. For structures over 100ft, Washington State now requires a registered SE.

We have made extensive use of PLS-CADD for checking clearances of transmission lines using LiDAR data, but have not made extensive use of it for structural analysis. Are you using PLS-CADD to do structural design all distribution poles? When I looked at using it for structural analysis of transmission with underbuilt distribution, I found it difficult to use reasonable loads for low voltage service drops and communication joint attachments.

 

[engratcorner]

Well, I am glad to know that there are electrical engineers using PLS-CADD. We have been using it to check the clearances between power lines and communication lines as per NESC standards and perform the structural analysis as well on existing distribution poles. Prior to doing this, we collect survey info on distribution poles and build them using PLS-POLE and make use of them in PLS-CADD.

When you say reasonable loads for service drops, are you referring to conductor tensions and insulator strength requirements?

 

[bacon4life]

A typical distribution pole might have the following:
a:3 phase conductors. The tension often varies by phase by at least 100 lbs.
b:1 neutral conductor
c:2-5 different communication messenger wires. Each messenger may have been strung 1 pole at a time, which will end up imparting net longitudinal load on the pole.
d:1 overhead transformer ranging from 15 kVA to 100 kVA. We do not have electronic records of the weight, dimensions and wind areas for each transformer, nor do we track which quadrant of the pole it is mounted on.
e:0-2 conduits for either underground services or communication drops.
f:2-8 service drops. Each drop may range from 50 to 300 lbs horizontal tension.
g:1-3% pole top deflection resulting from either the aforementioned unbalanced loads or soil settlement


We typically use fairly robust poles rather than trying use the minimum allowable pole size. The service drops and communication conductors are adjusted fairly frequently(i.e. more often than I want to remodel the line). When poles are replaced, the attachment tensions are all reset, and the adjacent poles are probably also impacted.