Moreover, reasonable lightning protection measures to consider regional and seasonal differences of lightning characteristics as a result of the upgrade of the lightning protection design method have been applied the actual system design. Therefore, the lightning characteristics of each region and season are requested accurately.
To solve the above-mentioned problems, the upgrade of the lightning observation techniques has been carried out since about 1980, and it has become to be able to clarify the statistical characteristic of the winter lightning. Moreover, it has become to be able to observe the ground flash density at each region and season more accurately than IKL map by applying the measured results of the lightning location and protection system (LLP) with Global Positioning System (GPS).
This report has aimed to summarize these observation data, and to contribute to the rational lightning protection design for power systems and the information sending to the world.
The main investigations are as follows:
1. Lighting parameter for power systems
__a. Classification of lightning current waveform observed in winter
__b. Duration of wave front, duration of wave tail, continuous current, and electric charge
__c. Relationship among peak value, steepness and wave front of lightning current
__d. Lightning path impedance
__e. Return stroke model
__f. Velocity of lightning stroke
__g. Reliability of LLP and method of using the observed data by LLP
__h. Lighting Characteristics of geographical, regional and seasonal data
2. Sensitivity analysis for lightning protection measures
3. Data comparison with foreign countries
4. Lightning observation parameters that will be needed in the future
©2005. The Institute of Electrical Engineers of Japan