Arc Extinguishing Chamber Research Articles

SF6 Experimental Study on the Variation Characteristics of Closing Prebreakdown Duration during Contact Deterioration of Circuit Breakers

The contact morphology change caused by high-current ablation will seriously affect the electric field distribution in the interrupter chamber, which in turn affects the closing prebreakdown arc duration, indicating that the prebreakdown arc duration can be used as one of the indicators to measure the contact ablation state. A circuit breaker simulated ablation test platform was established, and the voltage and current signals, electromagnetic field signals, and vibration signals in the process of circuit breaker closing were measured, and the closing prebreakdown duration was calculated. The results show that under the same size of the ablation current, with the ablation of the contacts, the closing prebreakdown duration shows an overall trend of increasing and then decreasing, and the larger the ablation current is, the larger the change in the closing prebreakdown duration is. At the same time, simulation verification was carried out, and the results show that the electric field distortion on the surface of the static arc contact inside the arc extinguishing chamber is the largest, and the ablation of the contact will further increase the degree of distortion of the electric field inside the arc extinguishing chamber. As the degree of ablation increases, the prebreakdown moment of the circuit breaker closing is advanced, and the prebreakdown duration increases.

Interruption characteristic of 3%C5F10O/97%CO2 gas mixture in a 40.5 kV circuit breaker

The C5F10O/CO2 gas mixture is one of the most promising SF6 alternative gases at the present stage, which was initially applied in high-voltage electrical equipment. This paper mainly studies the interruption performance of 3%C5F10O/97%CO2 gas mixture (k = 3%) with a charging pressure of 0.6 MPa in high-voltage circuit breakers. First, the thermodynamic parameters, transport coefficient, and net radiation coefficient were calculated for k = 3%. On this basis, a 40.5 kV circuit breaker was used as a prototype to establish the magnetohydrody-namic model for breaking 20 kA short-circuit current, and the arc temperature and pressure distribution in the arc extinguishing chamber of the circuit breaker were calculated. The LC oscillation circuit was used to build an arc-extinguishing characteristic test platform to verify the accuracy of the numerical calculation. Finally, based on the Mayr arc model and the critical electric field strength, the post-arc thermal breakdown and electrical breakdown characteristics of SF6, CO2, and k = 3% were quantitatively analyzed. The results show that under 0.6 MPa, the thermal breakdown performance of k = 3% is about 89.7% of SF6, which is nearly twice higher than that of CO2 and has better thermal breaking ability. The electrical breakdown performance of k = 3% is about 20.4% of SF6, and the probability of electrical breakdown in the front end of the fixed contact is high. This problem should be paid attention to in the design of high-voltage circuit breakers. This study can provide a reference for the development and optimization of environmentally friendly high-voltage circuit breakers.

Simulation study on arc motion process of 38 A low-voltage AC contactor under AC-4 conditions

In the process of breaking an AC contactor, the ablation of the contact by the arc current is an important factor affecting its electrical life, so the evolution of arc shape in the arc extinguishing chamber has an important influence on its breaking performance. To explore the influence of arc motion characteristics on its breaking characteristics, based on the theory of magnetohydrodynamics and considering the contact motion process, a three-dimensional air arc simulation model is established for the arc extinguishing chamber of an AC contactor with a fixed current of 38 A and the arc motion characteristics of the arc during breaking are analyzed. To verify the accuracy of the simulation model, a test platform was built. Under the same breaking conditions, the arc shape, arc voltage, and arc current were measured, and the experimental results were consistent with the simulation results. On this basis, an optimization scheme of the arc extinguishing component is proposed and its influence on the arc motion process is analyzed.

First Principles Calculation of Compatibility between Environmentally Friendly Insulating Gas C5F10O and CuW Contacts

The insulating gas and contacts in the arc extinguishing chamber of high‐voltage circuit breakers are the focus of research. In practical applications, the gas may react with the surface of the contacts. In this paper, C5F10O environmental friendly insulating gas, which has one of the potential alternatives, is selected as the research object. The compatibility of C5F10O and its decomposition products with CuW contacts was studied. This article uses the Dmol3 program based on density functional theory. The adsorption energy, transfer charge, and density of electronic states of C5F10O and selected typical decomposition products on the Cu (111) surface and Cu‐W surface were calculated, respectively. It was found that the original CuW metal properties were not changed before and after adsorption. The carbonyl O atom in C5F10O is easily adsorbed on the top of the Cu (111) surface, forming a stable CuO bond, which belongs to chemical adsorption. The interaction of the other three adsorption sites is weaker than that of the top site adsorption, which belongs to physical adsorption. C5F10O exhibits more active charge transfer and forms active W‐O chemical bonds when adsorbed on CuW surfaces than SF6. C5F10O has poorer compatibility with CuW alloy than SF6. C2F4 and C3F6 in the decomposition gas are chemically adsorbed on the Cu‐W surface. CO2, CF4, C2F6, and C3F8 do not form chemical bonds on the CuW surface. The adsorption stability of COF2 is weaker than that of CF4, C2F6, and C3F8. Compared with SF6 adsorption, the compatibility of C5F10O and CO2 on the surface of CuW contact is inferior to that of Cu contact. CF4, C2F6, C3F8, and COF2 in the decomposition gas can be compatible with the surface of the CuW contact. C2F4 and C3F6 cannot be well compatible with the surface of CuW contacts. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Simulation study on arc motion process of DC miniature circuit breakers

Based on the theory of magnetohydrodynamics, a mathematical model of air arc in the arc extinguishing chamber of a DC miniature circuit breaker was established. By coupling external circuit characteristics and contact movement process, the motion process of the arc was simulated and analyzed. On this basis, the effects of breaking speed, time constant, and magnetic field on the arc motion characteristics were studied. The study showed that increasing the breaking speed appropriately and adding appropriate magnetic field can improve the breaking performance of DC miniature circuit breakers. The research results can provide reference for the optimization design of DC miniature circuit breakers.

Decomposition mechanism of clean air based on ReaxFF molecular dynamics simulation and quantum chemical calculation

SF6 is widely used in gas switchgear but has a strong greenhouse effect. The development of an environment-friendly switchgear that can replace SF6 is a current research hotspot. As a SF6 alternative technology, vacuum arc-extinguishing chamber plus clean air insulation has shown high application prospects. The clean air inside the switchgear decomposes under the effect of high temperature and discharge; however, only a few studies focused on its decomposition mechanism. In this work, the decomposition mechanism of clean air and the effect of temperature on the decomposition are simulated at the atomic level based on ReaxFF (Reactive force field) molecular dynamics and quantum chemistry theory. Results showed that the decomposition of clean air mainly generates NO, NO2, and N2O. NO is the main product at high temperatures and thus can be the characteristic decomposition product of clean air. The clean air has good self-recovery characteristics, and its decomposition can be substantially promoted by increasing the temperature. The decomposition rates of N2 and O2 under 3000 K can reach 7.00% and 8.00%, respectively, which are twice and four times those under 2000 K. These results can provide theoretical basis and engineering guidance for the development of environment-friendly switchgear with vacuum arc-extinguishing chamber plus clean air insulation.

Study of Arc Interruption Characteristics under Rated Current in Low Voltage Circuit Breakers

The breaking capacity of rated current is one of the important indexes to evaluate the performance of circuit breakers, which is usually measured experimentally and cannot be analyzed in terms of the arcing characteristics of the opening process. Simulation methods based on the magnetohydrodynamic (MHD) model of the arc can be used to obtain the macroscopic motion of the arc within the interrupter and the interaction of the arc with the contacts, walls, and splitter plates. Therefore, this paper focuses on the arc interruption characteristics’ underrated current in low voltage circuit breakers by MHD simulation. A more accurate and effective field-circuit coupling MHD simulation model of low voltage circuit breaker products is developed in this paper. A nonlinear conductivity model of the sheath layer is considered to better simulate the near-pole voltage drop and bending processes after the arc has been cut by the splitter. The time-dependent magnetic field generated by the arc is considered in the calculation. Additionally, the real-time parameters of the external circuit are coupled to reflect the evolution of the arc characteristics under the action of the external circuit. The simulation results intuitively and clearly show the evolution of the arc during the breaking process. Through this, an arc extinguishing chamber can be designed to effectively regulate the arc interruption characteristics, thereby improving the breaking capacity of the circuit breaker. The accuracy and efficiency of the proposed simulation method is verified by experiments. This method can be extended to the performance analysis of AC/DC low voltage circuit breakers.

Simulation research on the pre-strike characteristics of SF6 circuit breaker

The pre-strike duration of SF6 circuit breaker closing is one of the indicators to measure the ablative state of contacts, obtaining the pre-strike characteristics of SF6 circuit breaker closing is very important to evaluate the electrical life state of circuit breakers. In this paper, the simulation model of the electrical and fluid coupling simulation of the 110kv SF6 circuit breaker is established, and the pre-strike characteristics of the closing process are studied. The results show that the maximum point of the synchronous midfield is always on the surface of the static arc contact. The density of SF6 on the arc-extinguishing chamber is almost constant; the pressure output of the pressure chamber has little effect on the pre-strike voltage curve. Under the phase voltage of 110kv voltage, the duration of the circuit breaker pre-strike duration is 0.9054ms, which is close to the measured value. Results can provide the basis for the actual life circuit life evaluation.

Research on the electric life evaluation technology of the arc extinguishing chamber of the 550 kV circuit breaker

When the circuit breaker is switched on and off, the phenomenon of arc ablation will occur. Under the action of the electric arc, the surface of the contact is constantly damaged, resulting in deformation and material evaporation. With the increase in the electric arc temperature, the material loss on the contact surface of the circuit breaker increases. In this paper, according to the three major factors affecting the electrical life of the circuit breaker arc extinguishing chamber—the state of the arc contact, the nozzle, and the SF6 gas—the corresponding test detection methods and evaluation methods are proposed. With the continuous accumulation of the breaking current, the effective contact displacement between the arc contacts decreases and the average contact resistance increases. The effective contact displacement decreases exponentially with the increase in the cumulative breaking energy. The content of CF4 can be used not only to characterize the discharge ablation on the surface of the nozzle insulating material but also to characterize the discharge decomposition degree of SF6 in the system by adding carbonaceous compounds. Through the experiment, it is suggested that CF4 should reach 600 µl/l as the threshold for judging whether the arc extinguishing chamber needs maintenance. This method can be extended to the working condition evaluation of the arc extinguishing chamber of other types of the SF6 circuit breaker.

Calculation and Structure Optimization of Electric Field Distribution of The 10kV Solid-sealed Polar Pole

As one of the core modules of the ring - net switch cabinet, the solid-sealed polar pole was used to seal the three-station isolation ground switch and vacuum arcing chamber together. The electric equipment was concentrated, which was prone to electric field distortion. In this paper, a three-dimensional simulation model was established based on the drawings of the solid-sealed polar pole. The electric field distribution under the initial structure was calculated based on the finite element method, and it was optimized by adjusting the thickness of the moving contact and epoxy layer, changing the radius of the metal pull rod in the control mechanism and adding the equalizing ring on the shell surface. The results showed that when the inner diameter of the moving contact was 20mm, the outer diameter of the air layer was 43mm, and the radius of the metal tie rod in the control mechanism was 18mm, the field intensity in the solid-sealed polar pole was relatively reasonable, but the maximum E-field intensity in the arc-extinguishing chamber gap between the contacts was up to 5041V/mm. It was necessary to carry out pressure withstand test to ensure insulation safety. The results of this paper could provide reference for the optimal design of the solid-sealed polar pole.

Dynamic evolution of arc plasma in a semi-enclosed arc-extinguishing chamber and its influencing factors

Multi-chamber arc-extinguishing has been widely researched and used to protect transmission and distribution lines from lightning. Its principle is to divide a long-gap arc into multiple short-gap arcs using multiple semi-enclosed arc-extinguishing chambers. To study the dynamic evolution of arc plasma in an arc-extinguishing chamber, we establish a three-dimensional simulation model of arc plasma in a semi-enclosed arc-extinguishing chamber by solving the Navier–Stokes and Maxwell equations. We analyze the dynamic evolution of an arc from the inside of the chamber to the outside. An impact current test platform is built and the arc motion is photographed by a high-speed camera, revealing the acceleration of the arc in the semi-enclosed chamber. Finally, the influence of chamber dimensions on key arc parameters is analyzed. In the simulation, the time when the arc completely moves out of the chamber and is extinguished is consistent with the experimental images, which verifies the accuracy of the simulation model. The arc temperature, chamber pressure, and airflow velocity first increase in an oscillating manner and then slowly decrease with time. The change of the opening diameter will lead to the obvious change of the arc temperature maximum. The opening diameter is the main chamber dimension that affects the arc temperature. The electrode spacings have the most obvious effect on the maximum pressure in the chamber. The minimum pressure in different chamber dimensions is lower than the atmospheric pressure. The influence of opening diameter, distance from central axis to closed side, and opening wall length on the maximum airflow velocity is the same, and the maximum airflow velocity decreases with the increase in these dimensions. The influence of electrode spacing on the maximum airflow velocity is opposite to them.

Simulation study of influence of the outlet elastic baffle on pressure in arc chamber during the interrupting process of low-voltage circuit breaker

In this paper, a bidirectional fluid–solid interaction method is established to investigate the influence of the outlet elastic baffle on the pressure in the arc chamber in the breaking process of a low-voltage circuit breaker. Based on the computational fluid dynamic method, the flow model in the arc chamber is established. The model of the outlet baffle, with consideration of the nonlinear behavior, is established by the finite element method. By introducing dynamic grid technology, the interaction process of deformation of the outlet baffle and arc chamber pressure can be analyzed. A simple arc extinguishing chamber with an outlet baffle is designed, and experiments with a LC oscillating circuit are carried out. By using a high-speed camera and a pressure sensor, the deformation of the baffle and the pressure of the arc chamber are measured in the breaking process. The simulation model is verified by experimental results. It is worth noting that the flutter behavior of the elastic baffle was observed in the experiments and in the numerical simulation. Through simulation analysis, it is found that the flutter behavior is caused by the first-order mode of the elastic baffle under the excitation of arc chamber pressure.

Application of THz-TDS Technology in on-line detection of vacuum degree of arc extinguishing chamber

Terahertz time-domain spectroscopy (THz-TDS) is a non-destructive detection technology for carrying information inside a sample through a wide-band terahertz pulse carrying medium information. This paper briefly describes the imaging principle, characteristics, development and application direction of THz-TDS technology. The theoretical basis of THz-TDS technology applied in vacuum degree on-line monitoring is analyzed and verified by experiments. The experimental results show that with the change of vacuum degree, the signal amplitude attenuation and time delay of THz spectrum will change regularly. It shows that the spectrum and absorption spectrum obtained by THz-TDS imaging technology can sensitively distinguish the change of pressure in vacuum environment, that is, the change of vacuum degree. At the same time, the related air environmental pollution information also has strong absorption characteristics in the terahertz band, which makes the use of terahertz spectroscopy technology to detect pollutants in the atmosphere have a good development prospect.

Increasing the breaking capacity of the 10 kV VAC in comparison with its own axial and radial magnetic fields

The research work considers vacuum arc-extinguishing chambers with axial and radial magnetic fields. The object of research is vacuum arc suppression chambers with an axial magnetic field of 10 kV, 20 kA and with a radial magnetic field of 10 kV, 40 kA as well as ways to increase the breaking capacity by changing the configuration for each type of chambers. The research work uses the method of mathematical modeling of physical processes in the Comsol Multiphysics software package, graphical modeling of chambers is performed in Compass v18. 0. The results showed that changing the geometric parameters of vacuum arc-extinguishing chambers can increase the breaking capacity. Based on the results obtained, it can be concluded that to increase the maximum cut-off current, it is sufficient to change the geometry of the vacuum arc-extinguishing chamber. In combination with other ways to increase the breaking capacity, it is possible to expand the area of application of vacuum interrupters - the most reliable, safe and environmentally friendly switching devices.

Diagnosis of Post-Arc Residual Plasma in Vacuum Breaker

The residual plasma in the gap between the anode and cathode has an important influence on the recovery characteristics of the medium after the arc current zero in the vacuum arc extinguishing chamber. A diagnostic system for post-arc residual plasma is proposed and designed to diagnose the density of residual plasma during sheath expansion. The experimental platform is built on the basis of the synthetic circuit and detachable vacuum chamber. The diagnostic system uses Langmuir probe array to diagnose the post-arc plasma density change in vacuum interrupter, which reflects the dynamic process of sheath expansion in the gap. The effect of different current sizes and contact spacing on residual plasma is discussed in this paper. The plasma densities diagnosed by different position probes are used to analyze the post-arc characteristics of vacuum circuit breakers from a micro-level. The accuracy and reliability of the diagnostic system are verified by comparing with the previous studies, which provides some reference value for the future research on the post-arc micro-characteristics of vacuum breaker.

Simulation Test Study on Combined Gap Structure of High-speed Railway Catenary

In order to deal with the lightning damage problem commonly existing in high-speed railway catenary, a combined multi-breakpoint arc-extinguishing and lightning protection gap device (CMALPGD) which can be applied to high-speed railway catenary is proposed in this paper. Based on the principle of gas production and arc quenching of the device, a three-dimensional dynamic (MHD) model of arc in the arc-extinguishing chamber is established. With the help of simulation software to simulate the changes of the temperature, conductivity and high-speed airflow velocity of the arc at the fracture of the arc-extinguishing chamber, it is known that the high-speed air flow generated by the arc-extinguishing device can quickly extinguish the arc and restrain the arc development, and the whole quenching time is about 2.5ms. At the same time, the arc-extinguishing test is carried out by setting up the test circuit under laboratory conditions, and it is found that the arc-extinguishing time of the device is about 3.0ms and the arc is not reignited for a period of time. The conclusions provide a scientific basis for the application of CMALPGD in high-speed railway catenary in the future.

Research on the process of arc deionization under explosive high-speed airflow in semienclosed space

To study the process by which an explosive high-speed airflow extinguishes an arc and the characteristics of arc dielectric recovery in a semienclosed space, this study investigates the principles and processes of the formation, development, and extinction of an arc under the action of a high-speed airflow. When the impact arc occurs in a semienclosed arc-extinguishing chamber, the high-speed air suppresses arc development. Due to the high-speed airflow, the arc cools at an accelerated rate; the arc energy weakens, breakpoints occur, and the continuity of the arc energy channel is broken, preventing the arc from forming in the arc-extinguishing chamber and extinguishing it. This article employs AUTODYN software to establish a model for high-speed airflow arc extinguishing in a semienclosed space and then reveals a process by which a high-speed airflow extinguishes an arc in such a space. To verify whether a high-speed airflow can extinguish an arc, we conduct experiments in which high-speed airflow extinguishes a large impact arc and a power frequency arc. We recorded the arc extinguishing process with high-speed and ordinary cameras. The time taken to extinguish the arc is approximately 7 ms, and the arc does not regenerate.

Lightning Protection of 10-kV Distribution Lines by Multiple Breakpoints Arc-Extinguishing Lightning Protection Gap

This article introduces a 10-kV multiple breakpoints arc-extinguishing lightning protection gap, which can solve the lightning protection problem of 10-kV distribution lines. In order to investigate the arc-extinguishing characteristics of the device, ANSYS' Fluent software was used to simulate and analyze the high-speed airflow-coupled arc process. A magnetohydrodynamic (MHD) model has been developed to analyze the temperature distribution of the arc plasma in the arc-extinguishing chamber. The experiment modeling the lightning discharge effect and the lightning impulse combined frequency coupling experiment are performed to validate the effectiveness of the device. The test results indicate that the power frequency arc was extinguished by the device within 0.3 ms and did not rekindle with the effect of the power frequency voltage.

Study of the Flow on No-Load Breaking of SF6 Circuit Breaker Based on Lattice Boltzmann Method

In the simulating breaking of SF6 circuit breaker with the finite difference method and finite element method, there are some disadvantages such as a long calculation time and a complex calculation procedure. In this paper, a new method which is based on the lattice Boltzmann method (LBM) is presented to simulate the breaking process in an SF6 circuit breaker. And the model of nozzle arc is established by the lattice Boltzmann method. The flow in the arc-extinguishing chamber is calculated with the LBM. The pressure and velocity fields of the upstream and throat of the nozzle in the chamber are obtained by the simulation. Compared with the test data, they are good agreement. The results show the feasibility and correctness of the lattice Boltzmann method in studying the evolution of gas flow of nozzle during the breaking.

Working principle and testing technology of circuit breaker closing resistor for 1100kV GIS

The closing resistor can suppress the operation overvoltage and release the energy caused by the overvoltage generated by the power system when switching the line. It is widely used in the ultra-high voltage system AC system. Due to the complicated structure of the circuit breaker with the closing resistor, and the closing resistance of the field is placed in the sealed casing or GIS arc extinguishing chamber, regardless of whether the circuit breaker is in the closing or opening state, the closing resistance is usually not connected. The circuit breaker of GIS is more complicated than the open circuit breaker, especially the circuit breaker structure of 1100kV GIS which is the most complicated, and the maximum resistance of the closing resistor and the closing time of the closing resistor are tested. To understand this, it is very important to understand the working principle and testing technology of the ultra-high voltage circuit breaker. How to carry out preventive tests at the substation site and obtain the technical parameters of the closing resistor has become a key technical problem to be solved urgently. This paper expounds the structure of the ultra-high voltage circuit breaker, analyses the working mechanism of the closing resistor, and gives the method of on-site pre-test, combined with the Yucheng UHV ZF27-1100 (L) GIS circuit breaker to explain and give a case of on-site testing of the pre-input time of the closing resistor was made.