Protection zone of the charge transfer system

Replacing the conventional lightning rod by a charge transfer system (CTS) improves significantly the lightning protection of structures against direct lightning strokes. The typical CTS consists of four major parts: an ionizer, a grounding system, a ground current collector and a grounding conductor connecting the ionizer to the grounding system. The protective performance of the CTS is based on a well known phenomenon, point-discharge current, when sharp edged objects such as grass, leaves, edges of structures, etc.. exposed to the electric field, start to emit current into the surrounding air. A space charge generated by the CTS under influence of the electric field of a thundercloud reduces the electric field strength at and below the CTS location. This reduced electric field strength makes the lightning discharge path between the tip of the lightning leader and the CTS the least preferable one from all other alternatives. However, when the electric field change is faster than the CTS response, a strong moving upward streamer is formed, and that creates the preferable path for lightning discharge into the CTS. That means that compared to the performance of a lightning rod, the CTS is able to collect lightning strokes from a larger area and has, therefore, bigger zone of protection. The paper offers a method of calculation of the protection zone for the CTS.