Cost-optimal spare parts inventory planning for wind energy systems

Abstract

For safe and reliable machine operation, maintenance, repair and overhaul (MRO) activities are required. Spare parts demand forecasting and inventory planning, which is an important part of MRO activities, must be accurate to avoid costs because of surplus spare parts or machine downtimes. The restriction of reduced accessibility to wind turbines during the winter months also has to be taken into account when planning maintenance activities and spare part inventories for wind farms. The presented model provides the most economic stock quantity under given environmental conditions. It is based on the proportional hazards model, which is extended to calculate the remaining useful component life time and derive required spare parts inventory levels. The presented model is validated, using condition monitoring data and environmental data of an onshore wind farm. Comparison of the spare part inventory prediction to wind farm's failure data proves the model's accuracy. Parameter analyses show that the model can be applied for spare parts inventory planning under consideration of environmental conditions. Keywords Proportional hazards model Á Spare part Á Inventory planning Á MRO Á Wind turbine This article is part of a focus collection on ''Logistics in the Networked Industry'' based on the BVL's 7th International Scientific Symposium on Logistics in Cologne in 2014.

Spare parts control strategies for offshore wind farms: A critical review and comparative study

“…The main task is to compare excess stock-keeping cost and shortage cost in order to find the cost optimal quantity. Schuh et al (2015) has done it in three following steps shown in Figure 4. The steps are: (a) system analysis, (b) demand forecast and failure prediction, and (c) inventory planning.…”

“…It is possible to find the surplus or stock out probability using equation ( 22) and eventually possible to calculate the downtime or the inventory cost. Minimum total inventory cost is calculated by Schuh et al (2015) as follows,…”

On the optimization of maintenance storage cost in industry a fuzzy logic application

“…Researchers also considered specific versions of the problem. Schuh, Schnider, Funke, & Tracht (2015) integrated a hazard model with expected environmental conditions to model the optimum quantities of spare parts for offshore wind turbines. Moharana & Sarmah (2016) defined the term, "associated spare items," for the underlying relationships that could exist between groups of spare parts.…”

Spare parts quantity problem under uncertainty - the case of entirely new devices with short life cycle

“…Extended SPQ models are variations of the classical SPQ model, involving additional losses due to the broken device, the purchase of parts at different moments, etc. (Bartakke, 1981; (1) 2(3) Bian et al, 2013;Fera et al, 2010;Fortuin, 1981;Gu and Li, 2015;Papathanassiu and Tsouros, 1986;Pastore et al, 2015;Petrovic et al, 1986;Rodriguez et al, 2013;Rustenburg et al, 2000;Schuh et al, 2015;Sheikh et al, 2000;Verrijdt et al, 1998).…”