| In substation renovation and expansion project, it requires the construction workers to measure the soft wire span with a tape in the case of power outage, the ground staff to calculate the soft wire cutting length with the empirical formula, and make the soft wire then climb the humanoid rack to install it. The installation process has not only made economic loss, but also compromised the safety of power grid operation, increased the construction personal risk of working at high altitude, and made the sag difficult to guarantee the three-phase consistency. The structure of 500kV substation outdoor power distribution unit is complex, the construction drawing made of dozens of pieces of two-dimensional plane is made by AutoCAD.It has many disadvantages:the limited spatial visualization and analysis ability, the inability to evaluate the installation effect before construction and design-faults made on computers.This paper made researches on overhead line suspension point space coordinates measurement, overhead line fabrication length mathematical model, VC++ and OpenGL language applied for developing software of overhead line length calculating as well as its three-dimensional simulation, around electric transmission line assembly and virtual simulation, with four points of details and innovations as follows:(1) Taken total station as the measuring tool, a non-contact measuring system of overhead line suspension point space coordinates is devised to accomplish the measurement of overhead line suspension point coordinates and then get the span and dispersion in high accuracy, under the condition of uninterrupted power.(2) By ignoring the impacts that insulator chain has on overhead line, the mathematical model of long-distance overhead line length is set up based on span, dispersion, wire and meteorological region. The software is cultivated based on VC++ language to implement it,with the emphasis on determination of control meteorological condition. The nadir stress of overhead line is got by getting the root of a cubic equation applying Newton iteration method,and then achieve the design sag and overhead line length.(3) Due to the short span of substation soft wire, the length and weight of insulator chain have direct effect on the fabrication length of soft wire. The mathematical model of substation soft wire fabrication length is set up based on strain insulator-chain, spacer, wire, meteorological region, control conditions, insulator, span, dispersion and sag, etc, aided by the calculating software of substation soft wire fabrication length devised by VC++ language and three-dimensional simulation diagram achieved by OpenGL.(4) By applying OpenGL, a three-dimensional simulation system of 500kV substation wire layout is developed, aiming at 500kV substation and analyzing general models of overhead soft wire hanging curve. Its advantage is in no need of computer simulation technicists and the 7 structure parameter setup templates can develop the three-dimensional simulation of substation wire rapidly. This system, taking advantage of hierarchical design, consists physical model, rule model and system integration. By applying OpenGL, it first devised insulators, human shape holders, beams, GIS and other physical models, then set up the mathematical models of isoheight, jumper, downlead for 500kV substations and connecting models for rule model base, finally through system integration show the effect of 500kV substation three-dimensional layout, supporting multi-angle observation. The system has good human-computer interaction and settable parameter, and is suitable for different designs of 500kV substation. |
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