The effect of a multi-fracture compression airflow arc-extinguishing structure interrupting the power frequency follow current

Abstract

To reduce the damage from the power frequency follow current of distribution lines, a multi-fracture compression airflow arc-extinguishing structure is studied. The structure is mainly composed of a compression tube, a metal electrode, and metal connection fittings, and the multi-fracture compression airflow arc-extinguishing body is formed by the combination of packaging and insulation fittings. The body and the air gap are parallel to both ends of the insulator. When lightning strikes, the internal short gap of the main body and the air gap break down, and the lightning arc enters the arc-extinguishing body through the breakdown channel. In the structure, the arc is compressed by force to form internal and external gradients of temperature and to produce jet airflow. The jet airflow acts on the subsequent power frequency follow current arc, which is suppressed and extinguished. In this paper, a model coupling an arc and a compressed jet airflow in a multi-fracture compression airflow arc-extinguishing structure is established theoretically and simulated by simulation software. Finally, a power frequency follow current interruption test is carried out. The simulation results show that a high-speed airflow of 600 m/s is formed around the fracture at approximately 0.99 ms, and the airflow is proportional to the rate of temperature variation. The test results show that the power frequency follow current of 1.289 kA is cut off within approximately 3 ms without a reburning phenomenon. The effect of power frequency follow current interruption is obvious in the structure.

Mechanism Analysis and Multiphysics Validation of Lightning Attenuation in Constrained Space

“…where F is the radial volume force, and the negative sign represents the force is pointing inward along the radial direction. When the current density is constant, the radial pressure distribution of the arc body is given by Equations (26):…”

“…According to the assumptions above, the arc plasma can be described by this model which satisfies the fluid characteristics described by the Navier-Stokes equation and electromagnetic field characteristics described by Maxwell equation, it mainly contains the following equations [26]:…”