Arc Entry Test - Lifetime Wearing

Once the attachment process has been evaluated using the different High voltage test methods, the ability of the structure to handle the effects of the lightning current must be investigated. The current waveform in the lightning strike is composed of several different components relevant to lightning verification testing, the first short stroke, the long stroke and the subsequent stroke.

In the arc entry test, oscillating current pulses of 20-50kA superimposed by a DC current are injected into the test sample. The impact simulates the arc root erosion appearing due to the conducted charge in primarily the long duration stroke, which over time will wear the air termination system. By applying extensive amounts of charge up to several thousands of coulombs in multiple discharges, the test method simulates the life time impact on the air termination system. The tests will show how often wearing components must be replaced, for instance whether service intervals of air termination systems should be 1 year, 5 years, etc.

The tests are performed according to Annex D of IEC 61400-24, with a number of discharges and charge content in each discharge.

The arc entry test is documented with a test report containing pictures and results.