Comparison of forecasting methods in preventive lightning protection – a case study

Recently a new approach was introduced in lightning protection incorporating the use of forecasting tools and preventive actions into one lightning protection system, the preventive lightning protection. The key feature of this protection system is that the hazard forecasting methods are planned according to the available preventive actions. The appropriate use of forecasting is very important in the terms of protection efficiency (and also cost effectiveness). This paper introduces three forecasting methods (zonal PLP, high reliability PLP, and fuzzy forecasting) and gives a comparison of the methods through a specific case study. The case study also gives a good opportunity to introduce the calculation involved in the forecasting methods. Zonal PLP means that there are certain zones defined around the object to be protected which serve as a hazard evaluation for the forecasting system. The advantage of this method lies in its simplicity, but it may result in many unnecessary alarms, thus decreased cost effectiveness. High reliability PLP on the other hand relies on individual thunderstorm cell monitoring, thus is more accurate. Due to the constant monitoring it requires much more resources. However by using the systems currently available, this method may be realized easily in real-time. Fuzzy PLP is a novel approach to forecasting. It is close to High reliability PLP in terms of real time monitoring, but this method involves the use of a fuzzy expert system. The expert system has the same input data as High reliability PLP, but it utilizes special fuzzy functions to decide on the alarming. The case study introduced in this paper addresses an important problem in lightning protection, the problem of refuelling airplanes. The object to be protected in the study is an airport, which may be endangered by a thunderstorm cell. In the paper besides the comparison of the forecasting methods, an overview is given of the methods and preventive lightning protection itself.