Specifics by measuring of lightning current with large Rogowski Coil

In this paper our experience of designing and using of a large Rogowski Coil (RC) for measuring of lightning currents is described. Some inconveniences regarding the use of large RC with circumference about 6 m to 20 m, namely closeness to resonance frequency during measuring, loss of low-frequency components of the current impulse tail part can be eliminated by presented here measuring circuit. Basically, this circuit represents a new approach of lightning current measuring, which was tested in laboratory and during real lightning events on a communication tower. The results are depicted and discussed in detail in this paper. Moreover, the possibility to measure both impulse and continuous current (CC - upward lightning from high measuring object) from the same RC is considered. Some time and frequency domain network simulations were carried out in EMTP-ATP and compared with transient and frequency response measurements. Our scientific investigations were simplified by using scripts, initially developed in FAMOS and in MathCAD. The algorithms and results of their work are presented here as well. Also, in order to obtain precise measurements, some measures against electromagnetic interferences have been realized.