Computation of Availability and Performance of Wind Turbine with Markov Analysis in India

This paper deals with the availability analysis for the wind turbines (WT) located in hill and main pass having uncertainty in wind. Availability is a key performance index for WTs. In this paper, the concept of Markov analysis (MA) is used to model the failure characteristics of the WTs for calculating probability and reliability of reaching various system states of WT having the capacities of 225 kW, 250 kW, and 400 kW. Due to uncertainty in the wind, the probability of component failure is independent of the past history. Hence MA is considered as the best mathematical tool for modelling WT with complex system. The field data obtained from the Muppandal site in India such as Mean time between failure (MTBF), Mean time to repair (MTTR), failure rate and repair rate are used to compute the WT availability, using ITEM Toolkit version 8.0.2 as a measure of performance. No attempt is made to analyze the individual state of the WT system. In this paper, for seven critical components, a resultant of 128 states has been analyzed. This analysis yields some surprising results that some WTs are the most unreliable due to the rapid failure of its sub assemblies in view of the very high uncertainty in the wind and frequent grid failures.