| Controlled switching technology also called synchronous switching technology, has been one of the cutting-edge topics of intelligent switch, which essentially used for opening or closing breaker at a chosen phase according to different characteristics of load. By means of this technique, the magnitude of over-voltage and inrush current occurred from electric locomotive auto-pass the phase separation can be reduced greatly, which not only effectively protected power system and electric equipments of locomotive from damage of electrical transient effects, but also increased the interrupting capacity of switches, improve the reliability of electric power system and customer power quality.This paper is object to mitigate the electrical transient occurred during switching process by operating the electric locomotive load using vacuum breaker with synchronous switching. The basic principal of synchronous switching and its critical factor analysis are proposed firstly, which indicate that permanent magnetic actuator (PMA) with electronic control has some advantages including less mechanical movable parts, rapid action, minor mechanical dispersion and stable operating times, which can ensure the contacts always close or open at the expected instant. Then perform a deeply study on the transient-process when electric locomotive auto pass the phase separation to provide academic foundation for further study on transient-process controlling.Then the paper proposed a method of switch controlling system based on the integration of controlled switching technology and auto-passing system with switch on pillar. In which some analysis and simulation of controlling system's characteristic and its required accuracy based on synchronous vacuum switch with PMA are performed. All the studies provide reference and support for the application of controlled switching to auto-passing system.Finally, a scheme of controlled switching system with a MSP430F449 single chip as core processor is proposed, which can achieve real-time monitoring to vehicle speed, as well as voltage and current on the traction line; perform real-time computing with zero point of voltage and current to control the switch action in the target phase. The scheme can also realize communication between the control system and traction substation via fiber-optic transmission, and locomotive using a radio frequency module, which can address the problem of data sharing and dispatching flexibility. |
