Research On Maintenance Decision Of Substation Equipments Based On Life Cycle Cost Management

Power grid enterprise belongs to basic service industries and public utilities, which is an important basic industry affectting national welfare and people's livelihood and bears important political and social responsibilities. The tansformation equipments undertake the mission of transmission, distribution as well as the safe and stable operation of power grids. The cost of these equipments accountes for a large proporation in the power system's investment. They are important assets of power supply enterprises, which also affect the cost and benefits of the enterprises. As a large number of tansformation equipments aging, reliability is decreasing year by year, the frequency of repairing is increasing, maintenance cost is getting higher and higher, so improving maintenance (technical reforming) is imperative. How to overall consider the tansformation equipments's whole process including planning, design, procurement, construction, operation, maintenance, technical reforming and scrap, to pursue the lowest life cycle cost and achieve system optimization under the premise of security and efficiency, is a major issue which is worthy of study and application and will has a profound impact on value preservation and increment of state-owned assets.In this paper, research work including:(1) Combining the characteristics of the various stages of substation cost, applicating life cycle cost management (life cycle cost, LCC)concepts and methods, analyzes the content and features of the components of substation's LCC, determines LCC's cost estimation formula, and proposes a LCC correction method based on the the average operating years and average funding cost.(2) Taking maintenance decision for substation equipments which have been put into operation as the breakthrough point, according to the use of economic life, estimates AIS (Air Insulated Switchgear) and GIS (Gas Insulated Switchgear) eqipments's cost in all stages.(3) Researches cost-effective methods, through the analysis of the relationship between LCC and reliability, proposes a specific formula applying cost-effective analysis in substation's maintenance (update) and construction. (4) Applying LCC analysis, carries out calculation, analysis, comparison, evaluation and decision-making for three maintenance(update) plans for 110 kV distribution equipments that have been in opertation: joint venture AIS (plan A)/ domestic GIS (plan B) /joint venture GIS (plan C).