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A new intelligent controlled reactor (ICR) was proposed. The reactance of ICR can be changed by a moveable magnetic-wedge, and be a large reactance when fault and lower in normal. The electromagnetic model was founded and the magnetic circuit was analyzed, then the design formula of ICR's reactance was deduced. The structure of ICR was primary designed and modeled by using ANSYS. The equivalent reactance...
The switching surge occurs due to the transient phenomenon in the opening and closing operation of the high voltage circuit breaker. It puts a strain on the circuit breaker components. The controlled switching device for high voltage circuit breaker reduces the contact wear and the stress applied to the component by minimizing the switching surge by controlling the contact moment during the switching...
When SF6 was designated as a green house gas to be reduced, there has been a wish to use an alternative insulating gas to replace pure SF6 gas. And a fluoroketon, C5F10O attracts great attention as a potential substitute. In this paper, the breakdown characteristics of C5F10O/CO2 as mixtures in nonuniform electric filed and the variation of the mixing ratio with elevation were studied. The positive...
SF6 has been widely used in electrical industry because of its excellent electrical capabilities. However, due to its extremely high Global Warming Potential (GWP), researchers have done lots of investigations on SF6 alternative gases during the last few decades. Unfortunately, all the substitutions have their own drawbacks and limitations and can't be applied in practice. In this paper, the critical...
It's increasing clear that departures from both thermal and chemical equilibrium exist in conditions relevant to high-voltage circuit breakers after current zero. The electron temperature (Te) is often higher than the heavy species temperature (Th). We are intended to investigate the effects of N2 contents on the electron temperature and non-equilibrium composition during the arc decaying process,...
CF3I has been recognized as an attractive insulating medium for substituting SF6 gas in high-voltage switchgear insulations, because it has low global warming potential (GWP) and an insulation capability that is 1.2 times greater than that of SF6. In this paper, the AC breakdown tests on CF3I/N2 gas mixture have been completed in a sphere-plate geometry. We reveal the effect laws of mixture content,...
Cu-Cr contacts have become so widely accepted that now they are used in nearly all the commercial medium-voltage, high-current vacuum interrupters. Sintering process can be classified into solid state sintering and liquid state sintering. This paper examined the surface of the contact according to sintering method and compared the ability to short-circuit. The surface was checked through a SEM. And...
Nowadays the phase controlled switching is a preferred method for capacitive switching. Thus the distribution of prestrike gaps is an important issue for the control strategy. The objective of this paper is to understand the distribution of prestrike gaps for the contact materials manufactured by arc-melted and infiltration preparing technology in the capacitive service condition of 40.5kV vacuum...
Predicting zeroes precisely and rapidly after a fault initiation is the basis of controlled fault interruption. However, none available algorithms could predict current zeroes within several milliseconds. The objective of this paper is to propose a fast estimation algorithm that can predict current zeros within 3ms after fault initiation. An algorithm is proposed based on an improved BP network. In...
To analysis the reliability of the permanent magnetic actuator, the life test of permanent magnetic actuator is carried out and the related parameters are measured. Traditional reliability evaluations are generally based on the failure life data. Due to the small samples of the life test, the performance degradation method is applied in this paper. By analyzing the degradation path of the related...
Mechanical characteristics, including the displacement curves of the movable contacts and coil current curves are the most common routine monitoring objects of high voltage circuit breakers to evaluate the machines' condition. Generally, a high-performance mechanical characteristic tester has the ability to offer dozens of parameters consisting of stroke, speed, magnitude of current and so on. Besides,...
This paper designs a fault diagnosis model for circuit breaker based on power dispatching system. The model has three levels including data level, criterion level and judging level. The data level consists of data obtaining, data handling and fault database. The criterion level consists of operating time characteristics model, fault tree and repository. The judging level is logical judging method...
Both experimental and numerical approaches have been done on switching arc plasmas for fundamental studies. In the experimental approaches, power-semiconductor switching has been used to control intentional current injections and voltage applications to switching arcs with a high accuracy in time. The systematic experiments provided the interruption probability property for different gas kinds and...
Through calculations and analysis of the transmission loop of a circuit breaker, this paper establishes a non-linear mapping relationship between the rotational output of the spring operating mechanism in the transmission loop and the linear motion of moving contacts in the circuit breaker arc quenching chamber. It interprets the reason of why there is some error in routine mechanical property tests...
On-load tap changer (OLTC) is essential in regulating the operation status of power transformers employed in modern power systems. While exploring power flow analysis, electromagnetic and electromechanical simulations by using the on-load tap changer, it is found that inaccuracy problem may occur with the assumption in conventional transformers that tap positions only affect the turns ratio parameter;...
Now the switchgear is extensively used in the power grid. The temperature rise of switchgear issues have attracted people's great attention. The heat production and dissipation effect of the main circuit conductor is be taken into consideration comprehensively. The heat generated by the main circuitis is calculated by thermo-electricity coupled analysis. The key issue in thermal analysis of switchgear...
To better assess the effectivity of UHF-PD sensor/system, two types of assessment procedures were established-the simple procedure and the complicated procedure. Both procedure required GTEM-Cell system and Simulation GIS/GIL. The element structure, the diagram and the signal transmission path of GTEM-Cell system and the Simulation GIS/GIL were demonstrated. The result data indicated that the discernment...
TEV (transient enclosure voltage), with large amplitude and high frequency, which affect the normal operation of the GIS secondary equipment. This paper is based on the theory of multi-conductor transmission line. The coupled relationship among three phases was decoupled by means of phase-mode transformation method, thus the enclosure transmission characteristic model of GIS is established. On the...
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...
The application of vacuum interrupters and vacuum circuit breakers for higher voltage level is strongly expected. In electrical insulation in vacuum, surface flashover on solid insulator is one of the main problems for the higher voltage vacuum interrupters. In this paper, through the review of our recent researches, we discuss on the initiation and development mechanisms of flashover in the configuration...
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