• Proceedings of the KSME Conference
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• 2000.11a
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• pp.688-692
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• 2000

This study proposed design parameters of opening spring of circuit breaker that cut off the over-current in order to protect the electric device about opening speed using the energy method. We simulated the opening kinetic energy, the potential energy of opening spring and the design parameters of opening spring with respect to opening speed of VCB (Vacuum Circuit Breaker)'s moving contactor which has 24kV 25kA break capacity. From the result of simulation the initial tensional force and the final tensional force of the opening spring chose 107kgf and 282kgf respectively. Through the dynamic analysis using ADAMS, We verified that the opening speed of moving contactor satisfied break capacity of VCB and analyzed opening dynamic characteristics of VCB such as the opening displacement, the opening velocity and the opening acceleration of moving contactor in time domain.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.190-195
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• 2013

Vacuum circuit breaker(VCB) has been widely used for interruption of load current and fault current for high voltage motor in the industrial field. Its arc extinguishing capability is excellent compared to other breakers. But it has the potential to cause multi reignition surge by high extinguishing capability. Surge voltage is generated by the opening and closing of VCB. Multi reignition surge of VCB is steep-fronted waveform. It may have a detrimental effect on the motor winding insulation. So, most of users install a protection device to limit steep-front waveform at the motor terminal or breaker side. So, most of users install a protection device at the motor terminal or breaker side. This protective device is surge absorber(SA) such as ZnO and RC type. In this study, we analyzed whether there is any effect when two type SA is applied to the VCB multi reignition surge. We confirmed that ZnO SA is slightly more effective than RC SA for reduction of multi reignition surge.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.578-585
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• 2007

A vacuum circuit breaker (VCB) with permanent magnet actuator (PMA) has been studied in this study. Electromagnetic field analysis and dynamic simulations have been carried out for optimal design of VCB by using commercial software Maxwell and ADAMS. This simulation model can be an effective method for the VCB, which has non-linear output force of PMA, friction, and impact for operations. An experiment has been conducted to evaluate correctness of the simulated model. By using this evaluated model, the displacement and velocity characteristics of the VCB have been simulated with following conditions : (1) The different output forces of PMA have been applied, (2) The friction conditions in follow lever shaft and moving part have been changed, (3) The mass conditions of moving part have been changed. The simulated results shows that the velocity characteristics are mainly determined by the output force of PMA. The effects due to the changes of friction conditions against the dynamic characteristics was small, and the mass conditions of the moving parts affect the velocity and a bouncing phenomenon of VCB. From these results, the optimal design conditions for the VCB have been derived.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1159-1164
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• 2018

Vacuum circuit breakers(VCB) are widely used for current interruption of high-voltage inductive loads such as induction motors. This VCB can be chopped off before the current zero due to its high arc-extinguishing capability. One of the outstanding features of VCB is that it can cut off high frequency re-ignition current more than other circuit breakers. If the transient recovery voltage generated in the arc extinguishing is higher than the dielectric strength of the circuit breaker, a re-ignition phenomenon occurs. The surge voltage of the re-ignition is very high in magnitude and the steepness of the waveform is so severe that it can act as a high electrical stress on the winding. If the high frequency current of one phase affects the other two phases when the re-ignition occurs, it may cause a high surge voltage due to the virtual current chopping. If the magnitude of the voltage allowed in the motor winding is high or the waveform level is too severe, it may lead to insulation breakdown. Therefore, it is necessary to reduce the voltage to within a certain range. In this study, we briefly explain the various phenomena at the time of interruption, analyzed the magnitude of the dielectric strength and the transient recovery voltage at the simultaneous three-phase interruption that can give the greatest influence to the inductive load, proposed a method to reduce the impact.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.381-389
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• 2003

Nowadays, Vacuum Circuit Breaker(VCB) is used in the most medium voltage level because vacuum has environment-friendly characteristics as well as excellent dielectric strength. In order to elevate the breaking performance, the improvement of vacuum interrupters and the driving mechanism should be proceeded. In this paper, the development of a Permanent Magnet Actuator could replace the mechanical spring mechanism which is the driving mechanism of existing VCB. The holding force and opening characteristics of magnetic actuator are analysed with FEM and the result is verified through experiment.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.141-148
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• 2015

In this study, the VCB(Vacuum Circuit Breaker) has been developed using the Recurdyn that is widely used on multibody dynamics analysis. The VCB consists of three main circuits with the VI(Vacuum Interrupter) and the main frame with the operating mechanism. This analytic model is validated by comparing the simulation results and the experimental results. Generally, in order to reliably cut off the breaking current, the opening speed of the VCB after contact separation has to be a 0.9~1.1m/s. Therefore, the study of the design parameters of the VCB is needed. To improve the opening velocity, Taguchi design method is applied to optimize the design parameters of a VCB with a lot of linkages. In addition, to evaluate the improvement of the operating characteristics, the simulation results are compared with the Recurdyn and experimental results with improved prototype sample.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.804-806
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• 2003

In these days the Vacuum Circuit Breaker(VCB) is used in most medium voltage level because VCB has merits of simple structure, long life, free maintenance and environment friendly characteristics. Most of VCBs adopt mechanical spring drive mechanism to operate vacuum interrupter, but this mechanism is composed of many components and needs frequent maintenance works. In this paper, we study about the VCB drive mechanism with Permanent Magnet Actuator (PMA). Design methods and design flows about PMA are presented. The magnetic equivalent circuit is used for elementary and detailed design to determine the size of PMA. Finite Element Method (FEM) analysis is performed to evaluate the behavior characteristics of PMA in both static and transient state. Finally we manufacture sample PMA and verify FEM analysis through experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1418-1421
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• 2003

The Vacuum circuit breaker is a kind of power circuit breaker and protect electric devices from over-current. In this paper we built a dynamic model of VCB driving mechanism using ADAMS. The development of the new circuit breaker with less energy and more compactable mechanism is focused. Through the dynamic model, the concept design of the new circuit breaker with less energy and more compactable mechanism is proposed, and then the detailed design is carried out through the design process based on the dynamic model.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.105-113
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• 2011

The study about three-phase synthetic making test using DC power has been performed in order to increase the making test capacity on Vacuum Circuit Breaker. And, it made possible to solve the limitations that short-circuit testing facilities can not fulfill the testing requirements of VCB exceeding three-phase 36[kV] 31.5[kA]. By using DC power and high speed spark-gap switch, this method made the equivalence with the pre-arc that occurred during the making process under the fault condition of power system. As results, KERI(Korea Electrotechnology Research Institute) could have capacity to carry out type test for VCB under three-phase 52[kV] 40[kV], which satisfies the IEC Standard.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.723-728
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• 2011

Since the performance of a vacuum circuit breaker (VCB) mainly depends on the spring operating mechanism, an analysis of the spring operating mechanism is required in order to improve the design of a VCB. In this study, the static stiffness of the spring was determined by using a material testing machine, and the test results were used to model the spring through computer simulation. The multi-body dynamic model of the spring was established by using the RecurDyn program. The dynamic model was verified by comparing the results of stem displacements and rotating angles of the brake shaft obtained from the simulation and from the experiments. After verification of the dynamic model of VCB, the cam profile of the VCB was optimized through multi-body dynamics simulation in order to improve the performance of the closing mechanism.