Test Document

Juraisin Lightning Protection Systems

For Safety and Peace of Mind

This is a translation of an overview document written by the Shibaura Institute of Technology after conducting the test of protective effectiveness for Juraisin. The document details the methods used to evaluate Juraisin and the results obtained during the test. Juraisin showed higher flashover rates when compared with standard lightning rods.

Overview of the Test

Lightning Protective Effectiveness of Juraisin

Shibaura Institute of Technology, Department of Advanced Engineering

Energy and Environmental Research Center

Katsuo Okumura, Center President

1. Introduction

At our Energy and Environmental Research Center, we have advanced research of the value of lightning protection equipment related to electric installation. This time we conducted a comparison test of the protective effectiveness of generally marketed lightning rods. The lightning rod selected for our test was manufactured by Hikari Industrial Corporation of Japanese Industrial Standard (JIS type), Ministry of Construction LR-1 model, product name “Juraisin.” In order to perform a comparison test of lightning protective effectiveness, we selected a lightning rod of identical standards produced by another company.

For our comparison test, we referenced the method used in the past for insulation distance in the air of high voltage engineering, namely, when deciding the distance between the electric conductor and ground objects. In particular, for our performance test, we referenced this method in order to the evaluate the lightning protective effectiveness of “Juraisin.”

2. Method of Testing

Diagram 1 illustrates the arrangement of the electric conductor (high-pressure side electrode) and the ground objects, or in other words, the lightning rods. For a high-pressure electrode, we used a stick electrode, fixed at a position of 666 cm above the ground. In addition, the two ground objects, or lightning rods, were placed so their tips were 163 cm above the ground at a distance of 522 cm away from the center of the stick electrode point. The horizontal distance between the two lightning rods was uniform at 278 cm. The applied voltage was negative polarity of lightning impulse wave form with a crest value of 3.9 MV of fixed voltage. For the performance evaluation, we calculated the flashover ratio during 20 times of identical voltage release, the timeline to achieve a flashover and the amount of standard deviation. Considering the influence on quality the arrangement of the positions of the lightning rods might have, we also repeated the same testing after interchanging the two lightning rods from right to left positions.

3. Test Results

(1) In regards to the protective effectiveness of the two lightning rods produced by the two companies

Regarding the two lightning rods, for purposes of convenience, we will first record the lightning rod arranged on the left side as “Lightning Rod A” and the lightning rod arranged on the right as “Lightning Rod B.” The results we obtained were that Lightning Rod A reached a ratio of 45% flashover while Lightning Rod B reached a ratio of 55%. When we interchanged the positions of the two lightning rods from right to left, and vice versa, Lightning Rod A showed results of 40%, while Lightning Rod B displayed results of 60%. As a result, we know that the two lightning rods showed relatively equal rates of protective effectiveness.

(2) Regarding the Protective Effectiveness of “Juraisin”

For purposes of comparison, when Lightning Rod (B) was placed on the right side and the “Juraisin” Lightning Rod on the left side, the rate of flashover for the “Juraisin” Lightning Rod was 65%. When the two lightning rods were interchanged from left to right positions, the “Juraisin” lightning rod achieved a flashover rate of 73.7%. The results that we achieved were considerably high and show a high rate of standard deviation. It can be conjectured that the lightning is received in the same location.

4. Conclusion

As a result of our tests, we came to the following conclusions regarding the protective effectiveness of the “Juraisin” lightning rod.

In the Protective Effectiveness Test we conducted for the “Juraisin” lightning rod, within identical conditions, from the high numerical value obtained, when an object that easily attracts lightning exists within the identical striking distance, we can expect a high value of protective ability (attracting the lightning and absorbing the lightning). In addition, the “Juraisin” lightning rod’s stability in absorbing the lightning in the same location was appraised as high.

In conclusion, in our test of protective ability conducted at this time, the comparative results, there is a matter of the distance of the discharge being different from actual lightning as well as the amount of discharge energy and such. Therefore, it is difficult to take our numbers and handle them as they are with theoretical value. However, we believe we were able to achieve valuable results with our appraisal.

Juraisin Air Terminal