Motion analysis of the particle in DC GIL considering the random collisions and gaseous resistance

Effect mechanism of dielectric‐coated electrodes on metal particle lift‐off in SF 6 gas

“…After the metal particles lift‐off, it will be speed up to the upper‐electrode by the electrostatic force, gravity, and gas resistance [10]. According to the formula of gas resistance in [10], the comparison of gas resistance F d and gravity G under the three kinds of gas pressure conditions of 0.10, 0.15, 0.20 MPa for 1 mm aluminium ball is shown in Fig. 3.…”

“…Assuming that the charge quantity q in the metal particles does not change during the course of motion, the electrostatic force of the metal particles does not change either, which means that the metal particles would be in linear motion with constant acceleration to the upper electrode in acceleration a , and the kinematic equation is [8, 10]: From the formula (1), the amount charge of metal particles q is In the formula (1)–(3), m is the mass of the metal particles, m = 1.47 × 10–6 kg for aluminium balls of 1 mm in diameter; s is the instantaneous displacement of the metal particles in m ; g is the acceleration of gravity, g = 9.81 m/s 2 ; E is the starting lift‐off strength of metal particles in V/m.…”

Partial discharge characteristics of free moving metal particles in gas insulated systems under DC and AC voltages

“…Three types of conductive particles were placed between the electrodes, and the voltage was measured when the particles began to move in the direct current field with an electrode gap of 32.7 mm. The lift-off voltages of particles of different materials are different [11,12,[14][15][16][17][18][19]. According to Equation (1), the initial charge of the particles is different, and the charge amplitude is linear with the diameter of the particles.…”

“…It can be seen that the PCD signal exhibits obvious oscillation changes. When the particle lifts off the electrode, the particle becomes charged [11,12,14], which can be expressed by Equation (1); while the charge on the particle has not been released through partial discharge, it can also be calculated by Equation (4). According to the experiment above, the charge that was tested was less than that of the charged particle.…”

“…Relatively extensive research has been carried out regarding the problems of the charging of particles and the resulting partial discharge [11][12][13][14]. The conductive particles are charged by the electric field in the chamber and move between the electrode gap to overcome the gravitational force.…”