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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 objective of this paper is to determine the lifetime of DC current vacuum arc in contact materials of CuCr50 and CuCr25. Commercial vacuum interrupters with contact materials of CuCr50 (50% Cr) and CuCr25 (25%Cr) were designed. A DC current vacuum arc lifetime circuit was set up. The vacuum arc was drawn by contact separation. The vacuum arc voltage duration indicated the DC vacuum arc lifetime...
The current zero period of vacuum arc determines the breaking performance of vacuum circuit breakers, and post-arc current is one of main parameters of current zero period. DC vacuum circuit breaker is one practical solution to solve the bottleneck of DC transmission circuit breaker. It is difficult to measure the post-arc current, when artificial current zero method is used to break the DC short...
A novel Medium Voltage Direct Current (MVDC) circuit breaker consisting of a High-Speed Switch(HSS) and a bridge-type commutation branch, which is based on current injection, is proposed and analyzed in this paper. The commutation branch of this design adopts bridge type, which can break bidirectional fault current rapidly by controlling thyristors. Meanwhile, after fault current is commutated to...
Contact over-travel and over-travel spring pre-pressure are important debugging parameters of the contactor, which affect contact breaking velocity and rebound. Based on the electromagnetic mechanism of actual products, a dynamic characteristic experimental system was built to realize the adjustment of over-travel and pre-pressure and the measurement of contact breaking velocity and displacement....
Enhanced switching performance during the interruption process is achieved when the arc quickly enters and stays within the splitter plate region with the arc itself remaining attached to the surface of the plates. It is well known that the vent design in low-voltage switching devices (LVSDs) has a significant influence on arc motion during an interruption event: however, there has been limited experimental...
High voltage circuit breakers are most important protective device in power system. Dynamic contact resistance measurement (DRM) is considered to be an effective assessment technique for contact ablation which has been widely used for many years. However, the contact resistance curves will be influenced by many factors, such as injected current and velocity. In power systems, circuit breakers often...
High voltage SF6 circuit breaker must meet the breaking requirement for large short-circuit current, and ensure absence of breakdown after breaking small current. A 126kV high voltage SF6 circuit breaker was used as the research object in this paper. Based on the calculation results of non-equilibrium arc plasma material parameters, the distribution of pressure, temperature and density were calculated...
In this paper, an interruption simulation model for 252kV Self-blast SF6 circuit breaker is built according to the MHD theory, using real gas model and dynamic mesh method. Aiming at acquiring the characteristics and the differences of interruption under different power frequency, the gas flow field at different power frequency 50Hz and 60Hz are simulated and compared. Seven analysis points at the...
The amount of switching operations of unloaded transformers increases with the developments of smart grids and integration of renewable energy sources. A random energization of an unload transformer can cause high amplitude and high frequency inrush currents. Controlled switching can eliminate the inrush currents effectively, the key to realize which is measuring residual flux in transformer core...
Vacuum degree online detection of vacuum interrupter has been investigated for more than 50 years. But, there is still no perferable means can be used to practical application. The change rules of Cu, H spectral lines intensities with pressure have been investigated in this paper. Further, the laser-induced plasma temperature and density are calculated using Boltzmann slope method and Stark broadening...
This paper proposes an improved method to measure vacuum online which includes signal processing circuit and control algorithm. Firstly, the equivalent capacitance, between vacuum circuit breaker contacts and the shielding cover, is analyzed by Ansoft software. The differences of equivalent capacitance between the condition of separation of contacts and the condition of contacts closure, are researched...
The measurement and analysis of the spatial morphology and dynamic characteristics of the electric arc plasma inside low voltage circuit breaker is an effective way to improve its breaking performance and modern testing techniques have been applied to the experimental study on switching arc plasma in recent years. However, these techniques usually need to destroy the extinguishing chamber wall and...
The clock synchronization technologies applied to controlling layer and primary equipment like intelligent switchgear of processing layer in intelligent substation are analyzed in this paper. IEEE1588 message timing mode, which can be accurate to nanosecond, is used as the mode of substation system, in order to fulfill the real-time and accuracy requirements of intelligent switchgears and remote control...
In our paper The effect of magnetron discharge pressure measurement on the actual pressure in vacuum interrupters (ICEPE TS 2015) it was reported that in 2013 vacuum pressures in the 10−5 mbar range had been measured in a batch of old vacuum interrupters which had been sealed for more than 30 years. This measurement was then repeated in 2015 and found to be in the 10−6 or 10−7 mbar range. It was proposed...
Aiming at the phenomenon that the arcing time is different when SF6 circuit breaker interrupts capacity current under the conditions of positive and negative polarity. So the capacity current breaking test by SF6 circuit breaker is used to study it, which can provide reference for the optimization of SF6 arc extinguishing chamber. In this paper, the interrupter structure of test prototype is introduced...
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...
Due to the favorable features of rapid breaking operation and short arcing period, the DC circuit breakers based on the principle of current commutation have attracted great attentions in the fault clearance of DC system. In these breakers, the current commutation between paths plays a vital role in determining the success or failure of interruption. To realize the commutation reliably and economically,...
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...
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