A current and vibration based detection system for lightning strikes on transmission towers

Abstract

Lightning strikes can lead to disastrous situations in transmission lines and towers and condition monitoring is a crucial step in mitigating the probable adverse effects associated with this natural phenomenon. The current work proposes a method and circuitry for a lightning strike detection system with current and vibration detecting features. Each tower in a network can be equipped with this detection system. The current detector uses a current transformer called Rogowski coil along with additional components in a circuit. Due to its reliance on an air cored coil, the Rogowski coil does not have any issues with magnetization errors and is able to measure and detect ac and fast changing impulse currents. It can be placed around a conductor where the lightning current is expected to flow. Simulation results were used to verify the behavior of the current detector with 300 mA and 100 kA currents over a frequency range from 1 kHz to 9.57 MHz. A small scale prototype was built that performed adequately and the experimental results obtained were in line with the theoretical and simulation results. The detection system also provides means of ascertaining which tower is closest during the moment of the strike through use of a dual-axis digital accelerometer by making use of the vibration at the moment of the strike and correlating that with the current detected. The vibration detector was tested using varying levels of vibration. The current and vibration detector were then unified via a microcontroller to make up the lightning strike detector.