Testing Method and Application for Impulse- Dispersed Current Around Earthing Devices in Power Transmission Networks

Dispersing current under lightning impulse has a significant influence on the safety of creature and equipment. In field application, there is a lack of a direct and effective measurement method of impulse-dispersed current around earthing devices in power transmission networks. To solve this problem, this article presents a calculation method of the current density and makes a sensor for measuring impulse-dispersed current in the soil. The sensor device is made using the flat-type electric field structure, and a water tank test platform is set to determine the optimal sensor device size, and the absolute measurement error of the sensor is not to exceed 8 A/m². Then, in order to verify the effectiveness of the sensor, impact simulation and test based on a hemispherical sand pool are developed, and the absolute error between measured data and simulated data is within 6 A/m². Finally, the impulse current density sensor has been utilized in the field project; and the measurement results could guide the site selection and renovation in tower construction.