From the series of articles "Are active lightning rods really active?".
Whatever the opponents of active lightning rods say, the idea of ESE-effect is flawless from the standpoint of electrodynamics and physics of gas discharge. Correctly choosing the amplitude and duration of the control voltage, you can encourage the development of a counter-leader and thus intercept the downward lightning at a further distance. Even better, if the supply of these impacts will be synchronized with the spread of the lightning. Not the ideology, but the technology is an obstacle here. The voltage source cecessary to control the lightning requires very significant material costs, and today it does not fit those small-sized devices that are available on the market of lightning protection products. Do not forget about multi-component lightning. To deal with them,supply of the control pulses is required at a frequency of 10 Hz. You won't get along without your own source of energy here, because the corona discharge in the electric field of the atmosphere does not provide the desired rate of energy storage in the formative capacity.
It is useful to forget about all these technological problems at least for some time and consider the consequences of mounting an active lightning rod on any facility. At the level of the lightning rod top on a moderate height, for example, at the height h=20 m, based on leaflets, protection radius at the ground level should be close to r0A=100 m. A traditional lightning rod would have 5 times less, r0≈h. Numerous observations show that the equivalent radius of the lightning contraction is approximately equal to rat ≈ 3h=3r0. Keeping the ratio rat≈3 r0A for an ESE-lightning rod, we will get rat≈15h≈300 m. This means that the contraction area for such a lightning rod is close to 0.3 km2 and the annual number of strokes into it, for the midland of Russia, is ~1 (about 25 times more often than for a conventional lightning rod).
Taking into account the results of the estimate it is worth considering the feasibility of installing an active lightning rod on your own home, especially if there is no danger with the lightning channel for it. Our theoretically active lightning rod, intercepting lightning, does not affect the level of electromagnetic influence from its current, but it will dramatically increase the frequency of strong influences from nearby strikes. This is hardly reasonable today, when the cost of microelectronic devices can be comparable to the cost of the building in which they are placed. But the producers of active lightning rods will get a chance of their unconditional inspection.
E. M. Bazelyan, DEA, professor
Energy Institute named after G.M. Krzyzanowski, Moscow
- Series of articles about lightning protection for beginners
- Series of webinars about grounding and lightning protection with Professor E. M. Bazelyan
- Elements of external lightning protection
- Consultations on the selection, design and installation of grounding and lightning protection systems