Математична модель виявлення зносу контактної системи при комутації вакуумного вимикача

Abstract

The paper considers the role of vacuum circuit breakers among medium voltage switching devices. The paper discusses the advantages of using vacuum switching devices and the features of the use of an electromagnetic latch as a drive mechanism. The influence of the circuit (on) and the opening (off) of the power contacts is described in the wear of the contact system of the switch. Consider the physical processes in contact contacts that occur during switching of the vacuum switch and their influence on contact system wear. In the short-circuit mode, the contacts can be welded in the closed position and there may be burning and melting the contacts when they are disconnected. The developed mathematical model makes it possible to determine the wear of the switching system when the vacuum switch is turned on and off. When the circuit breakers are closed, the total electrodynamic force of the contacts for each of the poles of the power unit is taken into account. When enabled, the wear of the power contacts is determined on the basis of a comparison of the current traction effort of inclusion with the total electodynamic force of the rejection over all contact system poles. When disconnected, the wear of the power contacts is determined on the basis of a comparison of the driving traction effort with the offset with the minimum allowable traction effort for the process of switching off the vacuum switch. If the difference in force when the switching is differs by less than the specified value δ from the total electrodynamic force of the contact rejection or the current tractive power when switched off differs by less than the specified value σ of the minimum permissible traction effort, switch contact system wear signal. The application of the proposed mathematical model will allow the service staff to be warned in a timely manner about the wear of the contact system due to the arc processes that arise in the arc-vacuum chamber of the vacuum circuit breaker.