Effect of Metallic Particles on Electric Field of AC Filter Circuit Breaker Arc-extinguishing Chamber

Abstract

In the past few years, several explosion cases have taken place in convertor stations due to continually breaking operation of AC filter circuit breaker, which brings a huge threat to the stability and reliability of the network. Preliminary analysis shows that switching current of AC filter circuit breaker leads to arcing contact burning, producing some metallic particles. These particles may cause the electric field distortion of the arc-extinguishing chamber and reduce the insulation strength of the equipment. To solve the problem, the research on the influence that the metallic particles bring to the electric field of arc-extinguishing chamber in ACF circuit breakeris carried out. First, the model of both 550 kV ACF circuit breaker chamber and metallic particles is built by means of Solidworks and Ansys based on the theory of numerical analysis of electromagnetic fields, and the field distribution without metallic particles is simulated and analyzed. Then, the effect of shape and radius of the metallic particles on the field distribution, and the effect of different locations on insulation strength are analyzed. It suggests that metallic particles add up the maximum electric field strength of breaker chamber, and the shape of particle causes discrepancy to the calculating result. With the radius of hemispherical particle increasing, the maximum field strength reduces. In addition, when the particle is located on the surface of static arcing contact, the influence reaches the maximum. Finally, the influence of breaking parameter on the electric field is analyzed, and the preliminary optimizing advice is proposed, that is, improving the minimum arcing time to 5 ms, so that the maximum electric field strength will be lower than the SF6 gas engineering breakdown field strength.