Substation Project Life-cycle Cost (LCC) Evalution And Its Decision-making System Design

Substation engineering projects at all levels are fields of importance inelectrical power transmission and distribution, and take up a great share in total gridinvestment. In order to maximize the assets effectiveness for GridCorporations,subjects as to how to design substation engineering projects moreeconomically will become important research topics.As for previous substation project designs, it was common practice to firstlyforecast roughly area long-range load, then estimate substation capacity need in theregion studied, and finally apply typical designs based on designers’ ownexperiences from the past.In that kind of design mode, it often ended up, with anreduced initial investment, with a high operation and maintenance costthereafter.Such designs came with great waste. At present, the life-cycle concept hasbeen successfully applied in various areas of power system engineering, a largenumber of research continues to emerge.The life-cycle concept in substationengineering designs, however, are studied conceptionally primarily without adetailed set of design evaluation process in which the design process can bequantified.This paper, based on the project of " Life-cycle Cost New Technology Researchin Substation Projects " from State Grid Corporation of China, studied the life-cyclebasic theory and substation project constituents decomposition in detail, andestablished the LCC model of substation projects.This paper proposed alife-cycle-theory-based substation engineering design evaluation process whichconsists of four steps: main transformer capacity and number optimalselection;distribution device type selection;typical design matching;key equipmentsselection and its life matching.The four steps mentioned above are closely integratedwith backward and forward linkages, they show the usage of life-cycle concept andestablishe a quantitative mathematical model. On the basis of this evaluation process,this paper has developed a the substation engineering design life-cycle optimizationand decision-making system,which solved the data interface, equipmentmanufacturers’LCC reporting application and system security,and described thedesign page functionality and database tables of each module.In the design of a220kV substation engineering project,this paper uses this evaluation process combined with the software analysis, and shows the consistency of evaluation resultsand expert verifications. This system not only quantifies the design process anddetails data tables, but also helps designers to reduce the work burden, coordinatevarious departments, thus greatly improves work efficiency. A substation projectwhich utilized the life-cycle cost evaluation has been put into operation, and resultsshow that equipment maintenance is significantly reduced with significant economicbenefits.