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In order to research the interruption process of vacuum circuit breaker in aviation intermediate-frequency (360Hz∼800Hz) power supply system, vacuum arc experiments are carried out in interrupter with the diameter being 41mm and with the contact material being CuCr50 alloy. It can be indicated from the results as follows: With the increase of frequency and peak value of the current, both the peak...
Ejected plasma used in gas spark switch has been proved efficient as a trigger method. However, the development and trigger mechanism are still to be revealed. In this paper, an experimental platform was built to investigate the influence of trigger pulse energy and polarity on the space-time shape evolution characteristics and the ejecting characteristic of ejected plasma. The results indicate that...
Pre-breakdown current evaluation is of importance for Gas Insulated Switchgear (GIS) under DC high voltage application. Even if very small, assuming constant polarity of the applied voltage, such currents represent a source of charges which continuously accumulate on dielectric surfaces, especially if these have high resistance. This can lead to a significant change in the distribution of the electric...
It is acknowledged that microscopic electric field enhancement on electrode surface in vacuum interrupters (VIs) is fundamental to the electrical breakdown of vacuum gaps according to the different breakdown initiating mechanism, such as the micro-particles initiating mechanism, electric field emission initiating mechanism and so on. The objective of this paper is to investigate the characteristics...
This paper reports dielectric recovery property measurements of CO2 and Air arcs under free recovery condition. In these measurements, the arc current and the voltage applied to the free recovery arcs were controlled with a high accuracy in time using power semiconductors. The recovery properties were measured by changing the application delay time td of the recovery voltage with a peak of 8.2 kV...
The insulation characteristics of solid materials in high voltage switches directly affect the service life of these switches, which is of great significance to the reliability of power system. The electrical aging lifetime of epoxy resin materials in solid insulation switches is studied in this paper. The electrical aging lifetime test is carried on the epoxy resin materials at room temperature with...
The insulation capability is a key indicator for designing a vacuum interrupter. A vacuum discharging process, especially the initial stage of it, is correlated to the capability. However, the effect of anode is still uncertain in a vacuum discharge process. The objective of this paper is to experimentally investigate the effect of anode on the initial stage of a vacuum discharge. A ICCD camera was...
The arc energy has an important influence on the breaking capacity of switches. Based on the theory of magneto-hydrodynamics, a simplified two-dimensional dynamic arc model of switch is established and the variation law of arc temperature, current and arc shape are analyzed under the conditions of different breaking velocity and load characteristics. At the same time, the arc voltage, arc current...
In vacuum devices such as vacuum interrupters (VIs), surface flashover events are one of the obstacles for developing their higher performance. It is believed that such a surface flashover in vacuum has a close relationship with a charging phenomenon on the insulator surface. Therefore, it is important to grasp the charging characteristics on the inner surface of the VI. In this study, we have measured...
Fundamental experiments were made for a DC arc in a separation process of a brush and a commutator segment. Firstly, we constructed an equipment composed of a fixed graphite-electrode (simulating a brush) and a movable copper-electrode (simulating a commutator segment). This equipment employed a sliding-movement separation process of the electrodes. From a waveform measured under a DC source of 12...
A two-dimensional (2D) rotary axisymmetric model has been developed to describe the formation and development of cathode spot in vacuum arc. The model includes hydrodynamic equations and thermal conductivity equation. Parameters used in this model come from experiments and other researchers' work. The simulation results show that when the energy flux density is 1.5∼3×1012W, discharge current is 1∼6A...
In vacuum interrupters, anode spot formation is commonly known as a high-current anode discharge mode and it significantly decreases the current interruption capacity of the vacuum interrupters. To understand the mechanism of the anode spot formation, the heat flux density delivered to the anode is of vital importance. The objective of this paper is to determine the peak heat flux density at a transition...
The objective of this paper is to determine the dependence of field enhancement factor β on power frequency (50 Hz) voltage in vacuum. A rod-plane vacuum gap was designed in a vacuum interrupter. Shots of ac power frequency voltage were applied at three vacuum gaps till breakdown occurred and the three vacuum gaps were 1.0 mm, 0.8 mm and 0.5 mm, respectively. The field emission current and applied...
In order to improve the breaking capacity of contacts, it is very important to find a better contact material. In this paper, the triggering experiments of plate contact with different material are studied to investigate the characteristics of vacuum arc. The current range is from 1kA to 9kA (rms). The gap distance is 3mm and 5mm. The arc appearance and the behavior of cathode spots are captured by...
A lot of work had been made in the vacuum arc in power frequency. But there are few research reports about high-frequency vacuum arc. In this paper, the arc appearance and development process have been studied under 250 kHz. A compact resistance-inductance-capacitance (RLC) series resonant circuit was designed to generate high-frequency vacuum arc between plate electrodes in a detachable vacuum chamber...
A well-known method of low voltage DC current interruption is to increase the arc voltage to exceed the electric source voltage. The objective of this paper is to experimentally determine DC vacuum arc voltage characteristics subjected to an external applied transverse rotating magnetic field. In the experiments, the DC arc current was in a range from 100A to 200A. A Transverse rotating magnetic field...
In order to study the characteristic of fault arc in aircraft electrical system, this paper is devoted to calculate chemical equilibrium composition and thermodynamic properties (mass density, enthalpy and specific heat at constant pressure) of reacting mixtures contained by air, Cu and polytetrafluoroethylene at temperatures of 300–3000 K and pressures of 0.02–0.1 MPa and simulate the corresponding...
A rotary interruption technology is expected to significantly promote the breaking performance of high voltage switchgear. When the technology is introduced into a fault current interruption, arc plasma is driven to mitigate the erosion pattern of contact surface. However, there still remains little understanding on the arcing behaviors between a pair of rotating electrodes. In this paper, it presents...
High voltage solar array (HVSA) and extreme high voltage solar array (EHVSA) are important demands for spacecraft in the future. The electrostatic discharge will be caused by the interactions between the high voltage solar array and the plasma in the space environment in LEO. The electrostatic discharge arc can cause short circuit in the solar array which affects spacecraft work, and even cause the...
Insulating liquid, because of high breakdown strength and superior self-recovery property, is widely applied to intense electron beam accelerator, transformer, and superconducting fault current limiters, etc. However, the formation of bubbles caused by heat transfer in power equipment seriously hurts the performance of the insulating strength in liquid. The objective of this paper is to study the...
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