IEC 62539:2007

FOREWORD
1. Scope
2. References
3. Steps required for analysis of breakdown data
    3.1 Data acquisition
    3.2 Characterizing data using a probability function
    3.3 Hypothesis testing
4. Probability distributions for failure data
    4.1 The Weibull distribution
    4.2 The Gumbel distribution
    4.3 The lognormal distribution
    4.4 Mixed distributions
    4.5 Other terminology
5. Testing the adequacy of a distribution
    5.1 Weibull probability data
    5.2 Use of probability paper for the three-parameter
         Weibull distribution
    5.3 The shape of a distribution plotted on Weibull
         probability paper
    5.4 A simple technique for testing the adequacy of
         the Weibull distribution
6. Graphical estimates of Weibull parameters
7. Computational techniques for Weibull parameter estimation
    7.1 Larger data sets
    7.2 Smaller data sets
8. Estimation of Weibull percentiles
9. Estimation of confidence intervals for the Weibull function
    9.1 Graphical procedure for complete and censored data
    9.2 Plotting confidence limits
10. Estimation of the parameter and their confidence limits of
    the log-normal function
    10.1 Estimation of lognormal parameters
    10.2 Estimation of confidence intervals of log-normal
         parameters
11. Comparison tests
    11.1 Simplified method to compare percentiles of Weibull
         distributions
12. Estimating Weibull parameters for a system using data
    from specimens
Annex A (informative) Least squares regression
Annex B (informative) Bibliography
Annex C (informative) List of participants

Describes, with examples, statistical methods to analyze times to break down and breakdown voltage data obtained from electrical testing of solid insulating materials, for purposes including characterization of the system, comparison with another insulator system, and prediction of the probability of breakdown at given times or voltages.