Mechanical design and stress calculations for overhead lines
(The Transmission Line Design Software and the Distribution Line Design Software)

JOVE Transmission (Transmission Line Design Software) and JOVE Distribution (Distribution Line Design Software) are specialised in overhead transmission and distribution mechanical lines design. It allows the user, starting from data on line's topography and on available material for building it, to choose the best possible places for all supports and to choose the necessary material, checking for the respect of all conditions on clearances and on stress for conductors, insulator strings and towers (each bar of each tower), at any possible climatic condition. Then the Transmission Line Design Software and the Distribution Line Design Software produce all necessary documents for control office and for site team that will build the line. Already available in English, French, German, Italian, Hungarian, Turkish, Arabic and Chinese, it will only take a week to have it translated in any other language, as soon as a customer will request it. Jove Transmission and JOVE Distribution are multilingual hence, a study done in any available language may then be printed in any other available language (as long as necessary fonts are available for Chinese and Arabic).

A FEW REFERENCES

A previous version of this software running on SUN workstation has been widely used in France when PCs where not yet powerful, that is around 1990. This version has also been used abroad by SORELBE (Bénin) and EECI (Côte d_Ivoire). The PC adaptation of the software developed by GC Software is used for Distribution lines by users as different as Merz and McLellan (Newcastle-England), COMELEC (Togo), TRACTEBEL (Belgium, including a copy transferred to Palestinian Electricity). The Transmission lines module has been purchased by SOGREAH, GTMH, NORELEC and EPS for France, and for export by REA (Rural Egyptian Electric Authority, 3 copies purchased through EDF International), OVIT (Hungarian Electricity), JIRAMA (Madagascar Electricity), ENERCAL (New Caledonia, including the latest Tower Structure module). Some users have both Distribution and Transmission lines modules as NKANYESI Consulting (Durban, South Africa, working for ESKOM), EPS (Egypt) or TOPRANK (Malaysia). It is also currently (November 2000) being under test in countries as various as China, Turkey, Senegal and India. The main steps in using the Transmission Line Design Software and the Distribution Line Design Software are the update of basic information on available material and on technical options, the topographic information acquisition, the tower spotting (usually starting with automatic spotting, then tailoring its result), final verifications with detailed modifications, and results printing and plotting.


BASIC DATA AND OPTIONS

The accuracy of results given by the software will depend on the accuracy of data given to it. That is why their input is object of all cares in JOVE Transmission (Transmission Line Design Software) and JOVE Distribution (Distribution Line Design Software) :

- Password protection: this allows to leave any young trainee use the software without any fear that he could disturb something in the basic data and options (that would be impossible to detect afterward as long as it would not be a huge blunder). The WINDEV type files used are such that it is impossible to avoid this protection with an independent editor or spreadsheet.
- Consistency and likelihood controls are performed for each input (so quick that it is done without a user entering correct data even noticing it).
- Numerous help button are available, especially each time a choice has to be done in a data list.

This basic data is concerning the conductors (weight, diameter, elasticity, etc...), the insulator strings (length, breaking load, ...), the towers (hooking points position, length of possible feet extensions, allowable stress, prices, ..., grouped in families from smaller to higher and wider and from weak to stronger), and the climatic assumptions (grouped into tables, so as to have all extreme conditions in different seasons at line site). For users who want to compute stress for each bar inside the tower and down to the foundations, more details on towers' bars should be given. The basic options concerns the customers for which studies may be done (technical options, and possible different basic data library for each of them), the specific rules that have to be applied (any national rule can be implemented), the different items that should be present on plotter outputs (including character' size, line's thickness and colour, title blocks, ...), and the topographical codes that the user wants to use for describing the obstacles (with the drawing he defines and the associated required clearances for each kind of obstacle).


TOPOGRAPHICAL DATA

It may be collected through a lot of different ways. The Transmission Line Design Software and the Distribution Line Design Software can read data previously registered in a spreadsheet, or even raw data produced by surveyors' theodolite or GPS (Leica, Sokkia, Topcon, _). The file produced includes for each point its cumulative distance to datum, the possible deviation angle, point's code (that is information on possible obstacle), and other information that may include text. The necessary topographical data for the Transmission Line Design Software and the Distribution Line Design Software may also be entered directly in the software, were helps and prompt are available, especially for entering traditional surveyors' booklet data, for using the proper code for obstacle, for computing the angle of line axis with obstacles as roads or other lines, and for other information linked to topography (zone were supports are forbidden, change of ground clearance, change in support's installation price due to soil quality or transportation problems, etc...). The result is a topographic profile drawn on screen, where user may see the ground level (in green, or in red for forbidden areas), obstacles, side slopes, ground clearance limit (in blue), deviation points (where it is compulsory to place a support, marked by a yellow vertical line). Schematic map may also be displayed. Zoom are possible as well for profile than for map.


THE LINE DESIGN

For each new study, the user is first guided in starting basic choices, including selection of material that will be default prompted during the study: phase and earth wire conductors, insulator strings, supports (towers or poles: for each line section studied, 4 different support families may be defined for suspension, and 4 others for tension -or for possible rigid support in case of distribution line-). Then the supports may be placed on profile either one by one, or using one of the two automatic spotting facilities, possibly several times each using different starting options (minimum and maximum span, catenary parameter or initial tension). This automatic spotting is very powerful, as a few minutes are usually enough (depending on used computer's processor velocity) for placing up to 100 supports for a section. But as man will always remain much more clever than the machine, it will always be possible for engineer to improve and correct this spotting. Modification of support spotting is very easy, either on a table were all information concerning each tower are placed (this may even be positioning different insulator strings at left and at right of a tension tower, or adding counter-weights for limiting the insulator string swinging on suspension towers), or, for main values (position, foot extension, ...) with the mouse at screen (using the zooming possibilities for a better definition).


RESULT EDITING

Height languages are already available for using the Transmission Line Design Software and the Distribution Line Design Software and editing its results: French, English, Hungarian, Italian, German, Turkish, Chinese and Arabic (for customers having the necessary font libraries available on their computer for those two last languages). Other languages should follow soon, depending on interested customers (Spanish, Portuguese, Croatian, Russian, Japanese, Hindi, ...??). Thus, any study done in any language may be printed in any other available language. All what have been described above as available for display at screen may be printed (for tables, at screen, on printer or in a file), or plotted (for drawings), using any printer or plotter known as available for windows. Drawing may also be placed on disk in DXF format, so as to be available for completion using specialised drawing software as AUTOCAD (© Autodesk), MICROSTATION (© Bentley).


TRANSMISSION LINE DESIGN SOFTWARE / DISTRIBUTION LINE DESIGN SOFTWARE

The main difference between "transmission" and "distribution" lines in JOVE software is that instead of transmission towers based on foundation blocks on which insulator strings are directly hooked, the distribution supports are poles driven in ground with at their top independent cross-arms where insulator strings are hooked. The transmission module allows to have up to 12 bundles each one having up to 6 phase conductors with 2 earth wire 'that may be different), while the distribution module is limited to only 6 phase conductors and 1 earth wire.


NECESSARY HARWARE

For running the Transmission Line Design Software and/or the Distribution Line Design Software, it is necessary to have a PC with a Pentium or compatible or above processor (or multiprocessor), running under Windows 95, 98 or NT, with 32 Mb RAM memory, + 4 Mb memory on graphical card, with a monitor as large as possible (17" minimum, so as to see 1024 x 768 pixels), diskettes and/or CD-ROM driver, printer and plotter. The place occupied on hard disk by the software, the documentation and user's data (except drawing outputs) is less than 50 Mb. But an additional 50 Mb should be available on hard disk for temporary registration of drawing outputs, and another 100 Mb for Windows' virtual memory. The files used may be local or on network (basic data can be shared by several users), with a local hardware lock for each user, or a network one on server.