A Probe Into Uncertainty Of The Risk Value In The Lightning Risk Assessment Based On Monte Carlo Simulation

With the uncertainty appears frequently in the real world, uncertainty is becoming the object for more and more subjects. Many subjects have put forward their own concepts and methods about uncertainty, such as randomness in mathematics and calculation for probability, concepts of risk and uncertainty in economics and methods for risk measurement, which promote the depth of uncertainty.Uncertainty is a realistic and wide spread phenomenon in lightning risk assessment, although there is a hope that the assessor can obtain a determined result based on scientific assessment, however, in the process to meet customer demand, the evaluators found assessment is full of uncertainty. The best evaluator who can do is make assessment and estimation of the possible situation only by virtue of historical data, information, one's own technology and experience, then get the assessment results. As a result, in a certain sense, assessment is both a science and an art.Currently, GB/T21714-2 risk assessment method is considered as the most reliable assessment methodology, like other methods, they all based on the assumption of complete information, which are deterministic approaches, the assessment results obtained are estimate of single point. But the reality is that the lightning risk assessment facing many conditions, including weather, environment, etc. which are mostly uncertain, with the deterministic method to study the big uncertainty of lightning risk assessment. The results of that evaluation will inevitably be challenged by the community of theory and practice.This paper breaks the traditional research model with the features of the deterministic, complete information, turn to the realistic background of uncertainty, uncertainty about parameters and risk value of lightning risk assessment have been systematically studied.Firstly, an overview of the uncertainty of lightning risk assessment has been carried out, uncertainty factors have been classified to help evaluators and users of assessment report to better understand and use assessment results.Secondly, Crystal Ball (Crystal Ball) software in the Excel is used to make Monte Carlo simulation of uncertainty of lightning risk assessment, a useful experiment is carried out from quantitative analysis.Thirdly, based on the theory of uncertainty, drawing on related disciplines such as methods and ideas of mathematics and statistics, using a combination of qualitative and quantitative methods to make mathematical and statistical description of uncertainty in lightning risk assessment. It is concluded that the most likely value at risk (the average or median can be used in steadily) can represent the point estimates, with a certain confidence level of the value range to indicate the uncertainty range, and transfer to the customer in the form of adding some text to explaining charts and tables. On the view of deterministic point, the existing assessment methods are supplemented and perfect.Finally, the uncertainty of lightning risk assessment is proposed and the conclusions of this study are formed.