Analysis of a New High-Speed DC Switch Repulsion Mechanism

Review of Scientific Instruments

et al. 2015

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Articles you may be interested inInvestigation on critical breakdown electric field of hot sulfur hexafluoride/carbon tetrafluoride mixtures for high voltage circuit breaker applications A new design of DC hybrid circuit breaker based on high-speed switch (HSS) and arc generator (AG), which can drastically profit from low heat loss in normal state and fast current breaking under fault state, is presented and analyzed in this paper. AG is designed according to the magnetic pinch effect of liquid metal. By utilizing the arc voltage generated across AG, the fault current is rapidly commutated from HSS into parallel connected branch. As a consequence, the arcless open of HSS is achieved. The post-arc conducting resume time (∆t c ) of AG and the commutation original voltage (U c ), two key factors in the commutation process, are investigated experimentally. Particularly, influences of the liquid metal channel diameter (Φ) of AG, fault current rate of rise (di/dt) and U c on ∆t c are focused on. Furthermore, a suitable U c is determined during the current commutation process, aiming at the reliable arcless open of HSS and short breaking time. Finally, the fault current breaking test is carried out for the current peak value of 11.8 kA, and the validity of the design is confirmed by the experimental results. C 2015 AIP Publishing LLC. [http://dx.

“…8. For HSS used in the test, which is introduced in our previous work, 21 the bridge contacts are adopted. VT_0 and VT_1 are both fast thyristors (KKC 3500-45).…”

Section: B Test Results Of Fault Current Breakingmentioning

confidence: 99%

Investigation of DC hybrid circuit breaker based on high-speed switch and arc generator

Review of Scientific Instruments

et al. 2015

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“…The key parameters including coil circles, materials of coil and metal plate, as well as the initial distance between metal plate and coil are determined from our previous work. 5 The vents of actuator, which are used to balance the pressure variation caused by the high-speed motion of metal plate, are arranged uniformly at close and open positions. It is assumed that there are n vents, respectively, at close and open positions.…”

Section: Numerical Modelmentioning

confidence: 99%

“…Traditional model of Thomson-type high-speed actuator is developed in coupling the electromagnetic and circuit equations, which has been introduced by Roodenburg et al, 4 Wu et al, 5 and Holaus and Fro¨hlich. 6 However, in these models, the variation of flow field in the actuator caused by the high-speed movement of metal plate is not considered, which may attribute to the following two aspects.…”

Section: Introductionmentioning

confidence: 99%

A new model for Thomson-type actuator including the pressure buffer

Advances in Mechanical Engineering

et al. 2015

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The motion characteristics and flow field variation of Thomson-type actuator have been investigated in this article, in which a two-dimensional axisymmetric cylindrical coordinate model is constructed and described by a set of multiphysical equations reflecting the flow field, transient electromagnetic field, electric circuit, and mechanical motion. The motion performance of the actuator and the pressure drag caused by the high-speed movement of metal plate are analyzed under different opening speeds. It shows that the pressure drag has a strong buffer effect on the actuator. The influence of the laminar and standard k À e models on the pressure distribution, velocity distribution, and motion characteristics is focused on. In comparison with the laminar model, the pressure drag of the turbulence model is much higher than the laminar model and is more beneficial for the buffer design of the mechanism.

“…The structure and parameters of HSS have been introduced in our previous work. 15 We assume that the short circuit fault occurs at 0.9 ms in the simulation.…”

Section: The Simulation Of Fault Current Breaking In Mvdc Systemmentioning

confidence: 99%

Research on a novel two-stage direct current hybrid circuit breaker

Review of Scientific Instruments

et al. 2014

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The DC hybrid circuit breaker based on high-speed switch (HSS) and parallel connected capacitor has been widely applied in the fault current breaking of DC system. However, when the current is commutated from HSS to the capacitor according to single-stage operation, the capacitor has to absorb a large amount of energy stored in the system inductance within very short time. Meanwhile, a high over-voltage rate of rise is especially prone to be produced between the contacts of HSS, which will lead to a failed breaking. As a result, a novel DC hybrid circuit breaker based on the two-stage operation is proposed and analyzed in this paper. By controlling the thyristors in the commutation branches, the fault current is fast commutated into the capacitor, which can not only realize the arcless open of HSS, but also decrease the over-voltage rate of rise significantly in comparison to the traditional single-stage operation. The simulation model of fault current breaking under different conditions in 10 kV medium voltage DC system is constructed. The simulated over-voltages of single-stage and two-stage operations in the case of fault current breaking are compared and analyzed. Finally, the fault current breaking test in the two-stage operation is investigated experimentally, which validates the feasibility and effectiveness of the simulation model well.