Optically Powered Lightning Current Measurement System for High-Tower Observation

The measurement of lightning striking the high tower is one of the most important ways to obtain the full-wave of lightning current. However, importance has never been attached to this important work until recent years in China. During the implementation process, many difficulties have to be overcome, such as problems relating to the current sensor, signal transmission system, and the power supply. In this paper, an optically powered lightning current measurement system composed of two current probes, an optical fiber link transmission system and a data acquisition terminal is designed for high-tower observation. The system has the following advantages: 1) multi range design is adopted, which enables the system to simultaneously measure the lightning leader and return-stroke currents; 2) two self-integral Rogowski coils are used as the lightning current sensor, thus making the full wave measurement of lightning current more accurate and easier; and 3) driven by laser energy, the optical fiber link allows the system to be immune to electromagnetic interference and less dependent on electric power. Such a lightning current measurement system is now installed on the Zifeng Tower (450 m, the world’s tenth, China’s sixth tall buildings, as of August 9, 2016), which is expected to record the current of lightning striking the tower.