Online Assessment of Contact Erosion in High Voltage Gas Circuit Breakers based on different Physical Quantities (original) (raw)
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Impact of Surface Morphology on Arcing Induced Erosion of CuW Contacts in Gas Circuit Breakers
2018 IEEE Holm Conference on Electrical Contacts, 2018
In this paper, the impact of surface morphology of contacts, in particular different microstructural parameters like size and distribution of contact ingredients, on contact erosion in high voltage gas circuit breaker is investigated. It is demonstrated that the size and contiguity of copper and tungsten zones play a key role in contact erosion so that the mass loss in one specific contact after interruption of the rated short-circuit current is 2.5 times higher than that of another one, with the same dimensions and material composition. It is shown that the arc roots tend to be formed on larger copper zones and if the zones are not confined by tungsten area, the arc cross section expands resulting in a higher evaporation rate of copper areas. In addition, it is emphasized that ejection of tungsten particles after evaporation of surrounding copper areas is another mechanism leading to more contact erosion, which has to be taken into consideration in contact erosion modeling along with molten contact splash and vaporization. Index Terms-arc contacts, contact erosion, contact morphology, microstructural image of contact surface.
IET Generation, Transmission & Distribution, 2021
Online non-invasive methods to assess circuit breaker condition have been under consideration in recent years. The combination of the arcing time and the short-circuit current recorded by protective relays can be utilized to assess the degrading impact of current interruption on arcing contacts. In many previous investigations, an integral over arcing time of different functions of current and voltage has been proposed to predict the erosion rate of arcing contacts. Although the arcing time is a crucial parameter for these indices, no easily adaptable method to online condition assessment is available. This paper proposes a method for online determination of arcing time based on the measurement of the switching time of the auxiliary contacts. Several experiments have been performed under no-load conditions as well as during short-circuit current interruption, on two circuit breakers with different trip coil excitations (AC and DC). The results show that the delay time between the contact separation instant of the arcing contacts and the switching time of the auxiliary contacts has a very low jitter. This enables precise determination of the arcing time by measurement of the switching time of the auxiliary contacts, which is accessible during the online operation of circuit breakers. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Journal of Energy and Power Engineering, 2014
The DRM (dynamic contact resistance measurement) in high voltage circuit breakers is a manner of evaluating the internal ageing condition of the chamber. DRM is similar to static contact resistance measurement testing, but instead of measuring a single value when the breaker contacts are closed (static value), the ohmic resistance is measured at various contact positions, from the beginning of the contact opening until a complete separation of the contacts. The relationship between the contact resistances of the new circuit breaker and the ageing circuit breaker in operation provides subsidy for the evaluation of both the main and arcing contact conditions. This research aims to analyze the correlation between the various levels of degradation of the contacts and the configuration of the DRM curve. This work considers curve samples from new breaker chamber contacts and different levels of degradation by acceleration tests.
The influence of electrode erosion on the air arc in a low-voltage circuit breaker
Journal of Applied Physics, 2009
This paper focuses on the numerical research of the influence of electrode erosion on the arc behavior during opening process of low-voltage circuit breakers. The mathematical model of three-dimensional air arc plasma considering electrode erosion is built based on magnetic hydrodynamics. The mass fraction equation of copper vapor is introduced to the model on the basis of traditional mass, momentum, and energy balance equations. The influence of copper vapor on the thermodynamic and transport properties of the gas mixture is considered in this paper. The distributions of temperature field, gas flow field, and mass fraction of copper vapor in the arc chamber are simulated. The arc root displacements and arc voltage, which takes account of the influence of electrode erosion, are calculated. The simulation results indicate that the immobility time of both moving contact and stationary contact is much longer considering electrodes erosion. The calculated voltage of the arc column during arc motion considering erosion is smaller because of the change in the electrical conductivity of air-copper vapor mixtures. Except for the numerical investigation on the arc motion considering electrode erosion, the experiment work is also carried out to support the simulation work.
Investigation Of Enclosure Burn-Through In Hv Gis Circuit-Breakers Due To Internal Arcing
B&H Electrical Engineering
Modelling of internal arc faults in GIS is a complex and challenging task due to a large number of mutually dependent and highly variable factors, which influence the whole process. This is especially the case in GIS circuit-breakers with high rated short circuit currents, where the risk of internal arcing is much higher due to the presence of the switching arc and contamination of SF6 gas caused by the arc and by the products of material evaporation. Severe conditions resulting from internal arcing ultimately determine its design limits and must therefore be carefully investigated. This paper focuses on one of the main effects of internal arcing, the enclosure burn-through, and presents a novel analytical approach to the estimation of the enclosure burn-through time, as a result of the combined thermal impact of the arc root, arc motion and mechanical stress due to pressure rise, establishing a relation between the thermodynamic and transport gas characteristics in the arcing chamb...
A study of multi-break HVDC gaseous circuit breaker performance by using black box arc model
Electrical Engineering, 2020
The development of the renewable energy and the need of medium-and high-voltage direct current circuit breakers are the keys in the development of medium-and high-voltage transmission systems. It can be used in high-voltage systems as cascaded interrupters. In this paper, the cascaded interrupters of gaseous circuit breakers are simulated using black box arc models. The influences of the models parameters on the arc interruption time are studied. MATLAB/Simulink program is employed to carry out this study. It is concluded that the simulated results by employing black box arc models achieve a success in multi-break HVDC gaseous circuit breakers simulation. Employing BBAM models has proved more flexibility to study the effect of different controlled and uncontrolled parameters on the multi-break HVDCGCB arcing time. That has proved more flexibility to study the effect of different controlled and uncontrolled parameters on the arcing time. From the investigated forty cases done to check the Mayr's model validity in the HVDC CD simulation, it is found that the values of P and which give acceptable outputs are at = 10 −6 s , and P in range of 10 7-10 11 W. The output of the case = 10 −6 s , P = 10 10 W, which is introduced in the paper has proved that when reached to 10 −7 s, the MOV current rises and drops and thereafter rises and gradually decreases. This may lead to CB failure; Com parameters influences on the interrupter performance are investigated and proved good simulation of the gaseous circuit breaker interrupter. The commutation parameters affecting the interrupter performance are investigated. Investigation of the change in the fault arc resistance and the fault location on the DC line on the arcing time is presented. Finally the impact of the changing of fault resistance value on arcing time and the damping resistance influence on the transient recovery voltage is also investigated. Additionally, the initial transient interruption and the metal oxide varistor voltages are analyzed. Keywords Gaseous circuit breakers • Black box arc models • Transient recovery voltage • The arc time constant Abbreviations ACZC Artificial current zero crossing BBAMs Black box arc models BCB Backup CB CBs Circuit breakers Com Commutation EMR Electromagnetic repulsion actuators HVDCGCB High-voltage direct current gaseous circuit breaker HVDC High-voltage direct current HVDCCB High-voltage direct current circuit breaker
The European Physical Journal Applied Physics, 2009
The presented study deals with the influence of the contacts materials on the evolution of the arc in low voltage circuit breakers. The commutation from the mobile contact onto the electrode is especially investigated in order to improve the breaking device performances. Hence, to preserve the qualities of the contact, the arc must leave this area as soon as possible. To undertake this study, several diagnostics are implemented. A measuring device is composed of magnetic induction sensors located outside the chamber. It allows the determination of the position and the volume of the arc during the breaking. Optical (ultraspeed camera) and electrical measurements are also performed with the technical support of Schneider Electric. Different current values (assumed peak current of 3 kA, 8 kA and 12 kA) and different natures of materials composing the electrical contacts have been tested. Copper contacts, different contacts on silver base obtained with different processes have been used. Experimental results show the influence of these various parameters on the arc volume and on the transfer of the arc towards the quenching chamber. Indeed, different dynamic behaviors are observed during the current transfer phase.
Electro-gas model breaking of capacitive currents within high voltage SF6 circuit breaker
2011 XXIII International Symposium on Information, Communication and Automation Technologies, 2011
This paper presents the modeling of coupled turbulent flow of SF6 gas and the electric field in high voltage switch gear during the interruption of capacitive currents, by using the socalled electric-gas flow model fields. Specifically, for a number of positions moving and stationary contacts during turn-off, the flow parameters of SF6 gas and the electric field between the contacts has been simultaneous calculated with finite element method. Using the calculated density of SF6 gas distribution and electric field strength at the reference conditions in the gas, one can calculate the real dielectric stress of the contacts position during switching-off of capacitive currents. During the modeling fluid flow SF6 gas applied the k-İ turbulence model and the Simplex method corrected by Chorin and Gresho.
On Treatment of Some Physical Properties of Gas in Simulation of High-Voltage SF6 Circuit Breakers
B&H Electrical Engineering
Simulation of unsteady flow of SF6 gas in a simplified high-voltage circuit breaker model describing the nozzle, contacts and their nearest surrounding is presented. SF6 is considered as viscous, compressible, real gas described by Redlich-Kwong model. Heat transfer is taken into account due to the gas compressibility. The heat source, triggered by the electric arc between the contacts, was out of the scope of the current research, thus it was not included in the simulations presented. Turbulence, caused by the gas viscosity, is described using realizable k-ε model. In the simulation model, one of the contact sides – electrodes, is considered as moving at prescribed velocity. The part of the space ‘swept’ by the moving electrode is considered as the gas with imposed artificially increased viscosity in order to imitate the rigid body behaviour. Thus, no moving parts of the computational mesh are used in the model. The conservation equations of mass, momentum and energy, given in inte...