Intelligent phase selection control system for 12 kV permanent magnet vacuum circuit breaker

Abstract

An intelligent phase selection control system for a 12 kV permanent magnet vacuum circuit breaker is composed of a control board and a driving board. After the control board acquires a current signal, a zero-crossing point is extracted from the signal to serve as a reference time point for phase selection control. After receiving a circuit breaker switching-on-off instruction, the control board conducts calculation to obtain a period of delay time and then controls a coil of the driving board to discharge electricity for switch on and off of the circuit breaker. Due to the fact that factors affecting phase selection time accuracy mainly include operating mechanism actuation time, driving board coil excitation time and reference zero point capture and program delay time, the switch on and off action time of a permanent magnetic operating mechanism is basically constant and the excitation time of the coil of the driving board is also a constant value, the accuracy of phase selection control mainly depends on program delay time. By reasonably controlling delay time, switch on and off of the circuit breaker can be achieved at the current zero-crossing point, so that switch on and off inrush current and operation overvoltage transient process are effectively avoided and working reliability of the circuit breaker is improved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an intelligent phase selection control system for a 12kV permanent magnet vacuum circuit breaker. Background technique [0002] As an important device for closing and breaking circuits in the power system, circuit breakers play an important role in the safe and stable operation of the entire power grid. Among them, the vacuum circuit breaker has the characteristics of high vacuum and high dielectric strength inside, and has the advantages of high dielectric strength and no need for frequent maintenance. It has been widely used in power systems, especially in the switching control of capacitors to achieve reactive power Compensation is the most typical. Vacuum circuit breakers have a variety of structures, from the initial manual to spring, hydraulic and permanent magnet mechanisms. Among them, the appearance of the permanent magnet mechanism greatly simplifies the str...

AI Technical Summary

Problems solved by technology

This method is complicated to operate, and the device is easily damaged due to frequent switching; while suppressing the transient process of overvoltage, a resistance-capacitance absorption device is used, and the principle is to increase the parallel capacitance of the protected equipment by connecting capacitors in parallel.

This kind of device has extremely strict requirements on the resistance value selection of resistors and capacitors. Improper selection will generate harmonics, which will increase the failure rate of the system.

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