Evolution of the RF characteristics of the impulsive noise in high voltage environment

Impulsive noise in air-insulated substations is created by partial discharges, Corona and gap noises. In order to install a wireless sensors network in such an environment, the impulsive noise must be characterized and studied to predict its evolution. The first observations made during a measurement campaign in power substation indicate impulsive noise RF characteristics depends on the feeding voltage of the equipment. In laboratory, a test bench with impulsive noise sources has been designed and used in order to verify the assumptions made from measurement campaigns and partial discharge theory. Using two impulsive noise specimens, the generator bar and the Tesla-coil, we study the impact of the source voltage and the inter-electrode distance (gap) on the RF characteristics of the emitted impulsive noise. The experiences confirm that, when the feeding voltage increases, the noise becomes more powerful both in time and frequency domains. The same is observed when the gap becomes shorter. Furthermore, the ISM frequency content of impulsive noise also increases, which could severely affect wireless communications.