Matching Study Of Short-Circuit Current Distribution Of Transmission Line And Extinguishing Characteristics Of ARC Extinguishing Gap

The extinguishing time of the arc extinguishing gap is affected by the short circuit current and extinguishing characteristics of the device. In order to improve the action reliability and success rate of extinguishing, we must choose the interrupting capacity reasonable according to fault current. And it is necessary to study the matching relationship of the protection and fault current.In order to reduce the lightning trip-out rate, the arc extinguishing time of the gap must be limited in10ms. Based on the transient calculation theory of transmission line, this paper finishes the line model of a110kV double circuit in Guangxi by using ATP-EMTP. The line adopts J.Marti model which has frequency varying characteristics and higher calculation accuracy, and the tower adopts four sectional wave impedance model, and the short circuit current distribution characteristic is calculated by setting different short-circuit point in the simulation. Secondly, this paper analyzes the extinguishing principle of the new type arc extinguishing gap basing on physical properties of the arc and frequency arc extinguishing theory. In the laboratory, we use impulse trigging test to test the movement speed of the device, and use arcing test of low power current to analysis the extinguishing characteristics. At the same time, based on the improved Mayr arc model and combined with the literature to determine the value of time constant in the model, this paper models the arc protection gap combining the insulator flashover model and arc model in the ATP-EMTP. Finally, according to the circuit model, the arcing gap model and lightning model, this paper simulates the lightning protection effect of the gap, and uses the dissipation power of arc extinguishing gap as control variable to study the matching relationship between the device and fault current, and determines the value of dissipation power of the gap under different short circuit current within the stipulated time. This will provide the basis for the application of arc extinguishing in practice.