Standard curves for economic application of wood poles and light duty steel poles using a personal computer

Abstract

Member Central Maine Power CompanyAugusta, Maine astract -A simplified. algorithm is presented which models the simultaneous wind and weight span capability for wood and light duty steel poles.The model is based on the mathematical derivation of the significant parameters which influence pole capacity and insulator swing angle considerations and was developed using a Personal Computer. The advantage is a user friendly, hini" input algorithm, which eliminates the need to run the more complicated-design and analysis program normally used for this type of application. A CAD system was used. to plot a family of curves from the numeric results in the form of application charts, The charts show wind span versus weight span for all pole sizes (classes) and pole heights, including line angle applications. Some typical applications are presented. Single pole wood and light duty steel pole structures supporting either a single or double circuit are commonly used for transmission line structures today. The transmission line design engineer has a need-to know the complete range of wind. and weight span capability of the single pole structure for proper structure spotting and economical line &sign. Complex solution algorithms are available which solve the structural resistance versus structural loads equation taking into account many variables such as type of material, pole height. structure geometry and environmental loa&. Both deterministic, NESC [l] and probability solution techniques are available. Several industry groups includlng IEEE [2] and EPRI [3] have sponsored techniques which yield. good results. These techniques work extrewly well if m specific structure has to be analyzed or designed. Generally one computer run or a long h a & calculation in made for a given material. class am3 pole b i g h t which results in o w solution, ie. o w point on the application curve. Our challenge was to davelop standard application curves for all pole heights. pole strengths and structure configurations, within cost effective engineering guidelines. This has been achieved. by daveloping a mathematical solution which is adaptable for use on TD 429-2 PWRD by the IEEE Transmission and Distribution Committee of the IEEE Power Engineering Society for presentation at the IEEE/PES 19Transmission and DistributionConference, New Orleans, Louisiana, April 2 -7, 1989. a standard. PC using a commercially available spreadsheet program and. with the results plotted on CAD. The technique is amenable to both the deterministic and probabilistic techniques for obtaining the wind-to weight span relationship of wood and light duty steel pole structures. The discussion in this paper applies to the more common deterministic method, but it is also applicable for the probabilistic approach. MATHEMATICAL MODELA model was developed for analyzing a single pole structure assuming the structure acted as a cantilevered column.Horizontal and vertical conductor and shield wire loads were represented in terms of resultant transverse and vertical loads. This provid...