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The characteristics of arc in DC contactors are a major factor affecting the breaking performance of small-sized contactors. Based on the magneto hydrodynamics (MHD) model, this paper obtains the temporal and spatial distribution of arc temperature by taking DC arc as its research objective and H2, N2 and He as arc extinguishing media. A removable arc chamber was adopted to build up a DC experimental...
It is necessary to monitor the operation state of the High voltage circuit breaker (HVCB) and analyze the fault by the related signal, the fault of HVCB operating mechanism is closely associated with coil current, mechanical vibration and other factors. The method of fault diagnosis for HVCB based on Hilbert-Huang transform (HHT) and support vector machine is proposed to analyze faults accurately...
In order to improve the dielectric recovery characteristic in high voltage circuit breaker (HVCB), the method of rotating gas flow to extinguish the arc is presented in the studying of a 126kV single-break SF6 CB. And a novel arc quenching chamber structure with blade nozzle is presented and three dimension (3-D) mathematical model of arc quenching chamber in SF6 CB is proposed. The Finite Volume...
Permanent magnet DC contactor has the advantages of simple structure, low energy consumption and low noise. A magnetic system structure applicable to DC contactor is presented in this paper. Based on the traditional structure of single coil and single stable position contactor, an auxiliary gas gap is added. By changing the size of the gas gap to change the attraction of permanent magnet, the whole...
Research on the external characteristic of the switch with contact is an important subject in breaking techniques nowadays. In this paper, based on the proposed experimental platform covering the arc fault diagnosis, load selection and wavelet neural network (WNN) design, a combination method of the experiment and simulation of the actual lines for the arc fault testing system is presented. And the...
In order to explain the mechanism of high voltage interrupter, a particle in cell method is used in our work to simulate the breakdown process before arc formation of vacuum and SF6 circuit breaker. The electrons and ions which play vital roles in this process are traced by Newton equation. The electrons from field emission, impact ionization and secondary electron emission are all considered in our...
In order to explain the mechanism of high voltage interrupter, a particle in cell method is used in our work to simulate the breakdown process before arc formation of vacuum and SF6 circuit breaker. The electrons and ions which play vital roles in this process are traced by Newton equation. The electrons from field emission, impact ionization and secondary electron emission are all considered in our...
There are great differences between vacuum discharge and common gas discharge. For short gap gas breakdown, the main reason can be explained as followings: electrons from the cathode emission are accelerated by the electric field and impact the anode which will release a lot of metal vapor. The ions produced by the collisions between metal vapor gas molecule and electron impact the cathode and secondary...
Investigation on arc shape in SF6 circuit breaker has very important significance to analyze arcs forming, moving and extinct principles, to reduce its dimensions and enhance switching capability. In order to facilitate to research arc characteristics, a set of dismountable SF6 model circuit breaker is designed in this paper. The experimental system of diagnosing arc plasma parameters is built based...
An intelligent digital flow rate measurement system is presented to replace the conventional hot-wire flow rate measurement system, which uses original analog feedback circuit. In this paper, the conventional Wheatstone bridge measurement circuit is replaced by a new Pulse Width Modulation (PWM) circuit for the purpose of energy conservation. The system employs a PIC18F452 chip to interface a thermal...
Sulfur hexafluoride is a gas with high electronegativity. For its strong adsorption to the electrons, it is widely used in the gas insulation. A microscopic model is established in our work to study the motions of particles in sulfur hexafluoride gas. Particle in cell method is used to trace the motions of the charged particles and the collisions between electrons, ions and atoms are simulated by...
The formation of arc in high voltage equipment is an unbalanced gas disruption and the principles of it are important in apparatus switching. For the complexity of gas disruption principles, the modeling and computer simulations to the beginning of gas disruption are vital in this domain. Particle-in-cell method is adopted in our work to disperse the Boltzmann equation and build a mathematical model...
A microscopic model is based in our study which adopted the particle-in-cell and Monte Carlo methods to simulate the behavior of the electrons at the beginning of the discharge. The distance between the plane electrodes in our study is 64 mm. The gas temperature is 300 K and the DC voltage applied to the electrode is 1000 V. We trace the motions of a large amount of the electrons and assembled average...
In order to certify the function of ion to the gas discharge, a model of direct current discharge of argon, which includes the elastic and charge exchange collisions between ions and neutral gases, is examined using the particle-in-cell (PIC)/Monte Carlo collision (MCC) simulation. The structure of our electrode is one dimension and for the velocity of the particles, three dimensions calculation is...
With the increasing of used quantity and voltage label of vacuum circuit breaker (VCB), the stability and reliability of VCB have very important significance for the reliable running of transmit electricity system. How to detect the mechanism characteristics of VCB, and obtain the characteristic parameters through the detecting data, and obtain the regularity of status examine and repair of VCB through...
Based on the theories of arc and gas discharge, a novel hybrid arc model in vacuum circuit breaker is proposed, considering the factors influencing on the arc formation from both microcosmic and macroscopic views. The evolution from initial discharge channel forming with breakdown to steady arc state is simulated. The results show that the radii of discharge channels are enlarging and the shapes of...
A flat-plate and pin-plate electrode gas discharge model based on fractal theory has been established in this paper. And to show the influence of the variation of electric field on the discharge routine development, the whole gas discharge process has been simulated and quantificationally analyzed. Moreover, the combination effect of the electric field and the random consideration on the discharge...
Nozzle plays very important role to control the gas flow during the interruption for SF6 circuit breaker (CB). Due to the higher non-linear global mapping relationship between interruption performance of SF6 CB and its nozzle structural parameters, artificial neural network (ANN) and genetic algorithm (GA) were applied to the nozzle parameter optimization of SF6 CB on the basis of the non-linear mapping...
A novel permanent magnet actuator (PMA) for mining vacuum circuit breaker (VCB) is presented in this paper. Which is monostable, has two coils and able to break the VCB when the fault of low-voltage happened. And can detect the voltage variation in main circuit at each instant. When the fault of low-voltage happened, it can automatically break without additional detection and control of apparatus...
A novel scheme combined the intelligent monitoring and fault diagnosis of mechanical characteristics for vacuum circuit breakers (VCBs) is proposed. The main principle of monitoring and diagnostic is stated and the design of hardware and software has been realized. By applying the developed on-line monitoring and diagnostic system, the mechanical characteristics of VCBs can be obtained and the detectable...
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