Characteristics Of Breaker Research Articles

A novel controlled switching strategy of back-to-back capacitor banks considering the prestrike characteristics of vacuum circuit breakers

Controlled switching of capacitor banks is an effective way to suppress the inrush current during capacitive-making operations. The objective of this paper is to determine the influence of the prestrike characteristics of four types of vacuum circuit breakers (VCBs) combined with two types of controlled switching strategies on the suppression effect of the inrush current. The four types of VCBs are cup-type axial magnetic field (AMF) single-break VCB, spiral-type transverse magnetic field (TMF) single-break VCB, cup-type AMF double-break VCB and spiral-type TMF double-break VCB. The prestrike characteristics of the four types of VCBs are investigated by synthetic tests. The two types of controlled switching strategies are the traditional controlled switching strategy (the closing command depends on the mechanical touch instant of the two contacts in VCBs) and the novel controlled switching strategy (the closing command depends on the 50% pre-arcing time ta50 of the VCBs). The results show that the spiral-type TMF double-break VCB combined with the novel controlled switching strategy is the best choice for applying back-to-back capacitor bank controlled switching.© 2017 Elsevier Inc. All rights reserved.

Research of the quality of functioning of low-voltage electric devices as a part of electrical complexes

THE PURPOSE. To investigate the problem of evaluating the energy-efficient operation of low-voltage switching devices installed in electrical complexes, to analyze the current state of the Russian market of electrical devices and to develop an algorithm and models of the main technical characteristics of circuit breakers of electromagnetic starters and contactors of various manufacturers.METHODS. In solving this problem, the ratio of the nominal current of the device and the resistance of contacts and contact connections of devices of some manufacturing plants is investigated. The analysis of experimental data showed what kind of functional dependences of contact resistances on the rated current have.RESULTS. Approximating functions have been developed based on the results of experimental studies of the value of contact resistances from the main nominal parameters of automatic machines, electromagnetic starters and contactors of some manufacturers.CONCLUSION. The article develops an algorithm and models for evaluating the energy efficiency of operation of low-voltage electrical devices, allowing to specify the amount of power (electricity) losses in equipment and recommended to increase the reliability of calculating electricity losses in low-voltage networks of electrical complexes.

Waveform Correlation Analysis Method for Mechanical Characteristics of Circuit Breaker in Intelligent GIS Equipment

Gas-insulated electrical appliances (GIS) have the characteristics of small footprint and low cost. Therefore, GIS is widely used in intelligent substations. However, once the GIS fails, there will be shortcomings of long maintenance cycle, which seriously affects the normal life and production activities. Based on this, on the basis of summarizing and analyzing the GIS intelligent technology, this paper studies the correlation analysis method of the mechanical characteristic waveform of the intelligent GIS equipment circuit breaker from the aspects of equipment intelligence, device development and software development,corresponding theoretical guidance is provided for the practical application of intelligent GIS equipment circuit breakers.

Research on electrical contact fault characteristics of GIS circuit breaker based on vibration signal

In order to analyze the vibration characteristics of GIS equipment when the contact is poor, we established a threedimensional model of 40.5kV circuit breaker by using the magnetism and solid coupling method. By changing the ratio of the close contact area of moving and stationary contacts to the total area of moving contacts (contact ratio), the situation of poor electrical contact was simulated and analyzed. The simulation results show that, when the contact ratio is constant, the current increases from 1000A to 3000A, and the acceleration of the contact also increases. In the case of the same current, the acceleration value when the contact ratio is 0.3 is greater than the value when the contact ratio is 0.6. When the contact ratio is 0.3 and the current is 3000A, the acceleration amplitude of the component with the frequency of 100Hz is the largest, which is 0.07m/s2. After research and analysis, it is shown that the vibration signal is based on 100Hz as the fundamental frequency. At the same time, multiple frequency components such as 300Hz, 600Hz and some other high-frequency components are generated. Therefore, the contact state can be judged through the measurement and analysis of the vibration signal.

Research on motor drive technology of highvoltage circuit breaker

In this paper, a technology of high-voltage circuit breakers (HVCBs) driven by motor directly has been studied. Through simulation calculation and test measurement of test prototype, the motion characteristics of circuit breakers driven by motor directly are analyzed. The results of research show that the rotor inertia and output torque of motor are the key parameters to realize drive by motor directly. The driven by motor directly can meet the requirements of closing and opening operation, and can realize the real-time control of opening and closing operation process of HVCBs.

Скоростная видеоспектроскопия сильноточного вакуумно-дугового разряда с медь-хромовыми электродами

The processes of channel contraction of a high-current vacuum-arc discharge and plasma formation in the anode region are of high actuality in terms of improving the switching characteristics of vacuum circuit breakers. In present paper the spatial-spectral structure of the discharge and its dynamics were studied with the videospectroscopic apparatus complex. The obtained data clearly show changes in the charge composition of the anode and cathode macrospots plasma in the process of changing discharge forms.

Characteristics of a Superconducting DC Circuit Breaker According to L and C Elements of LC Divergent Oscillation Circuit

Currently, we are developing an AC/DC conversion technology with the development of power semiconductors. Accordingly, DC is attracting attention because it is advantageous in the current transmission system. However, it has a problem that the cut-off technology required for DC system operation has not been secured yet. We are researching and developing a DC cut-off technology in several ways. We proposed a model that combines a superconducting fault current limiter and a DC circuit breaker. This is a configuration which a superconducting fault current limiter and a mechanical DC circuit breaker are connected in series. The superconducting fault current limiter limits the initial fault current and the mechanical DC circuit breaker cuts off the fault current. The mechanical DC circuit breaker consists of a high-speed DC switch, a LC divergent oscillation circuit and a surge arrester. This creates an artificial zero-point by affecting the blocking of the DC fault current according to the LC diverging oscillation circuit. In this paper, we analyzed the effect of the LC divergent oscillation circuit on the superconducting DC circuit breaker according to Reactor (L) and Capacitor (C). As a result, we analyzed the operating characteristics of the superconducting DC circuit breaker according to the application of the LC divergent oscillation circuit using the PSCAD/EMTDC program. Also, we confirmed the characteristics of the initial fault current limit rate of the superconducting fault current limiter and the possibility of controlling how the LC divergent oscillation circuit affects the DC arc generated at the opening of the mechanical DC contacts.

Operation Characteristics of Mechanical DC Circuit Breaker Combined with LC Divergence Oscillation Circuit for High Reliability of LVDC System

DC systems are modernly starting to come into the spotlight again due to the carbon-neutral policy, the development of semiconductor devices for power, and the increase in digital loads. We need to prepare in advance solutions to problems that may arise from fault currents due to transients for future DC power grid models. In the case of DC, there is no current zero-point because there is no frequency. Therefore, a large switching surge is generated when the circuit breaker cuts off the fault current. The possibility of insulation breakdown is greater than that of AC in severe cases. We consider power semiconductors or superconducting current limiters as an alternative. However, DC breaking cannot be safely achieved by itself. For reliable DC breaking, mechanical circuit breakers must be used with them. Among the mechanical shut-off methods, we adopted the divergence oscillation method. It has the biggest advantage compared to other methods in that it has a simple structure by composing passive elements and can artificially create zero current. In addition, it can be applied to a power semiconductor and a superconducting current limiter to perform a high-reliability cut-off operation. In this paper, we conducted simulation analysis by configuring the DC power grid and DC cut-off system through the PSCAD/EMTDC program. Results confirmed that the application of the LC divergence oscillation circuit can reduce the cut-off time and reduce the power burden of the mechanical DC circuit breaker (MCB).

Improving the cam profile of the spring operating mechanism of vacuum circuit breaker based on energy matching

High-voltage circuit breakers are important protection and control equipment in power systems. In order to understand the mechanical characteristics of vacuum circuit breaker, the mathematical relationship between the released energy of closing spring, the stored energy of opening spring and overtravel spring and the rotation angle of output crank arm is studied. The characteristic curve between the released energy of closing spring and the rotation angle of output crank arm and the characteristic curve between the stored energy of opening spring and overtravel spring and the rotation angle of output crank arm are drawn by MATLAB. In order to improve the matching of energy release and energy storage characteristic curves, a method of improving cam profile is proposed. The dynamics simulation model of spring operating mechanism of high voltage circuit breaker is established and the original cam and adjusted cam are imported into the dynamics simulation model of mechanism. The simulation results show that the adjusted cam improves the closing speed of vacuum circuit breaker. This helps to reduce the stress on the parts of the vacuum circuit breaker and increase the service life of the vacuum circuit breaker.

Simulation Research on the Post-arc Dielectric Recovery Characteristics of Multi-break Vacuum Circuit Breakers

The dielectric recovery characteristics are very important for the successful interruption of the vacuum circuit breaker. In order to explore the influence of the post-arc dielectric recovery characteristics of the multi-break vacuum circuit breaker on its breaking, this article establishes a simulation model of the multi-break vacuum circuit breaker and a 750kV short line fault simulation circuit in MATLAB. By adjusting the dielectric recovery characteristics of different breaks, the critical dielectric recovery rate (The minimum dielectric recovery rate of the break when the circuit breaker does not break down) under different conditions is finally obtained. In addition, the influence of the equalizing capacitor on the critical recovery rate is also explored. It is found that the smaller the grading capacitance, the greater the voltage of the break, and the greater the critical dielectric recovery rate.

Analysis of breaking overvoltage characteristics of DC circuit breaker

Analysis of breaking overvoltage characteristics of DC circuit breaker

The applications of anisotropic electrodes in vacuum circuit breakers to increase the switching life

The article analyzes the disadvantages of the vacuum circuit breaker, the transients that occur during switching, as well as the processes that lead to a decrease in the contact system resource. The simulation of the vacuum circuit breaker electrodes was performed using the COMSOL Multiphysics software package. The possibility of increasing the energy characteristics of vacuum circuit breakers by using single-crystal electrodes of copper, nickel, and iron as overlays is shown. A contact device for a vacuum circuit breaker with arc-resistant pads made of anisotropic materials has been developed.

Исследование переходных процессов анодного пятна сильноточной вакуумной дуги методом скоростной спектроскопии и видеорегистрации

The processes of plasma formation in the anode region of a high-current vacuum arc discharge are of high actuality in terms of improving the switching characteristics of vacuum circuit breaker. In present paper the dynamics of the radiation spectrum of anode region was recorded with the system that allows time scanning of a spectrum. In parallel, there was high-speed videorecording. The obtained data clearly show changes in the charge composition of the anode spot plasma in the process of changing discharge forms.

Non-permanent Pole-to-pole Fault Restoration Strategy for Flexible DC Distribution Network

As the structures of multiple branch lines (MBLs) will be widely applied in the future flexible DC distribution network, there is a urgent need for improving system reliability by tackling the frequent non-permanent pole-to-pole (P-P) fault on distribution lines. A novel fault restoration strategy based on local information is proposed to solve this issue. The strategy firstly splits a double-ended power supply network into two sin-gle-ended power supply networks through the timing difference characteristics of a hybrid direct current circuit breaker (HDC-CB) entering the recloser. Then, a method based on the characteristic of the transient energy of fault current is proposed to screen the faulty branch line in each single-ended power supply network. Also, a four-terminal flexible DC distribution network with MBLs is constructed on PSCAD to demonstrate the efficacy of the proposed strategy. Various factors such as noise, fault location, and DC arc equivalent resistance are considered in the simulation model for testing. Test results prove that the proposed strategy for fault restoration is effective, and features high performance and scalability.

Study on the Influence of Reignition on Electrical Life Distribution of Low-Voltage Circuit Breakers

This study analyzes the recovery voltage changes when a low-voltage circuit breaker opens with load and short-circuit faults and explains the reignition types under different recovery voltages. Reignition probability models of a single-pole contact and three-pole contact under different reignition types are established. The variation law of the contact erosion amount with the arc starting phase angle is analyzed. The distribution characteristics of the electrical life under three reignition types are obtained by simulating the low-voltage circuit breaker electrical life with a random arc starting phase angle. The results show that the electrical life of contacts obviously decreases after reignition, and that the electrical life changes differently with different reignition types. Specifically, the electrical life of a single-pole contact and three-pole contact is reduced by different degrees for the same reignition type. Hence, the influence of reignition on the electrical life distribution characteristics of a low-voltage circuit breaker cannot be ignored.

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.

Characteristics of a Mechanical Circuit Breaker with New Induction Needle and Magnets Type to Extinguish a DC Arc

Permanent magnets are currently attracting much attention as they are used in various application devices requiring high magnetic force. There are many types of permanent magnets with different properties, and they need to be tested for suitability for the applied devices. Sintered NdFeB permanent magnets have a large coercive force and are used in a variety of application systems. In particular, they are being used in circuit breakers to protect the DC transmission and distribution systems, which are actively being developed now. DC maintains a constant current value because it does not have a frequency. Thus, it is very difficult to interrupt large transient currents when an accident occurs. Therefore, a new type of induction needle and a permanent magnet near a mechanical break contact were combined. This induction needle is serially connected to a ground wire. This new breaking technique extinguishes the arch that occurs between the contacts by pushing it to the ground using an induction needle. The permanent magnet applied here, however, must be strong against a high-temperature arc that occurs quickly, and must generate a high magnetic force. Simulations were conducted with FEM (finite element method) and TDM (time difference method) using Maxwell, an electronic analysis program, and a permanent magnet that is appropriate for use as a component of a circuit breaker was selected. Consequently, it was found that the use conditions of permanent magnets varied by the arch generated in the mechanical circuit breaker.

State Evaluation of SF6 high Voltage Circuit Breaker based on improved Radar Chart and Catastrophe Progression Method

The comprehensive on-line assessment of power equipment health status was an important research content of power production and maintenance.According to the operation characteristics of SF6 high voltage circuit breaker, the hierarchical evaluation model of high voltage circuit breaker was established, and the subjective and objective weights were fitted and optimized by multiplication synthesizer; the improved radar chart method was applied to the importance evaluation of circuit breaker index; the final evaluation result of circuit breaker was obtained according to the catastrophe progression method, which made the evaluation process more intuitive and concise, and avoided the subjectivity. A practical example showed that the proposed model could objectively and effectively evaluate the state of high voltage circuit breaker.Compared with the traditional radar chart method, the improved radar chart method combined with the catastrophe series method solved the problems of information sharing and non-unique evaluation results among the indicators in the traditional radar chart method, which made the evaluation results more accurate and reasonable.

Time-Resolved Analysis of SF6 Arc Plasmas in a Laboratory Model Chamber for Circuit Breaker

This article presents time-resolved analysis of SF6 arc plasma generated in a laboratory-scale model chamber prepared for studying the characteristics of a circuit breaker. During the arc discharge, the optical emission spectra are measured by a high-speed spectrometer under various operating conditions. The time-resolved electron temperature and density values are determined using the well-known Boltzmann plot and Stark broadening methods, respectively, for the measured Cu I, S II, and F I emission lines. Moreover, the temporal evolution of the electrical conductivity of the arc plasma is deduced from the measured electron temperature and density values, depending on the operating conditions. In our experimental conditions, it is revealed that the electrical conductivity of arc plasmas is mainly determined by Coulomb (electron–ion) collisions as opposed to electron–neutral collisions due to the much higher Coulomb collision frequency compared to the electron–neutral collision frequency. Both the electron temperature and density were found to increase when the discharge current is increased at a fixed gas pressure, resulting in an increase of the electrical conductivity. When the gas pressure inside the model chamber is increased, the electron density is increased as well, but the electrical conductivity does not change significantly due to the slight change in the electron temperature. The present study will be helpful for investigating the performance capabilities of circuit breakers because the electrical conductivity, the most important parameter to guarantee successful circuit breaking at points near the current-zero, is determined by the temperature and density of the electrons.

Dynamic Simulation Optimization of Vacuum Circuit Breaker Based on Virtual Prototype

In order to study the mechanical characteristics of the vacuum circuit breaker, virtual prototype technology is used to establish a dynamic simulation model of the operating mechanism of the VS1 vacuum circuit breaker, and the dynamic characteristics of the opening and closing process of the circuit breaker are obtained. Then on this basis, in order to reduce the closing bounce of the circuit breaker, the various parameters of the mechanism that affect the closing bounce are selected as design variables for optimization and improvement. The simulation results prove that appropriately increasing the preload of the contact spring can effectively reduce the closing bounce.