Vacuum Circuit Breaker Research Articles

High Voltage Circuit Breaker Vibration Signature Indices Evaluation for Condition Assessment

Abstract The importance of the high voltage circuit breaker for the power system’s safe and reliable operation is paramount. This research aims to analyse and provide the most significant high voltage circuit breaker health state indices based on the non-invasive vibration fingerprint measurement method. Results obtained and presented in this paper are validated on the data set acquired from the vacuum circuit breaker.

Study on Arc Evolution Behaviour of Breaking Short Circuit Current for a Fast Vacuum Circuit Breaker

Abstract A fast vacuum circuit breaker (FVCB), driven by an electromagnetic repulsion mechanism, has an extremely short opening time, and in coordination with the controlled switching technology contributes to breaking a short circuit current with the minimum arcing time. The objective of the paper is to determine the arc evolution behaviour of fast vacuum circuit breakers with a minimum arcing time. A 40.5 kV vacuum interrupter (VI) was used, which was equipped with a pair of CuCr50 (Cr 50 wt%) axial magnetic field (AMF) contacts. The diameters of the contact were Φ50mm, Φ58 mm and Φ65 mm respectively. The arc evolution behaviour in the drawn arc experiment was photographed by a high-speed camera through a glass envelope of the VI. The experiment results showed that an initial intense arc tended to evolve into a diffuse arc when the arcing time is larger than a critical arc diffusion time under a certain opening velocity. The critical arc diffusion time for the vacuum arc is defined as arc evolving from the instant of contact separation to an appearance of separated cathode spots. For a Φ50 mm cup-type AMF contact, the critical arc diffusion time decreases from 0.7 ms to 0.46 ms, with the increase of the opening velocity from 2.52 m/s to 4.65 m/s. What’s more, for a Φ58 mm cup-type AMF contact, the critical arc diffusion time decreases from 1.0 ms to 0.58 ms with the increase of the opening velocity from 2.52 m/s to 4.65 m/s. For a Φ65 mm cup-type AMF contact, the critical arc diffusion time decreases from 1.30 ms to 0.64 ms with the increase of the opening velocity from 2.52 m/s to 4.65 m/s. The critical arc diffusion time increases with the increase of the diameter of the contact under the same opening velocity.

The characteristic analysis of the operational overvoltage caused by the vacuum circuit breakers on High-speed trains

The characteristic analysis of the operational overvoltage caused by the vacuum circuit breakers on High-speed trains

Investigation on arc characteristics in cup‐shaped contacts with different structure for transverse magnetic field vacuum circuit breaker

AbstractThe cup‐shaped transverse magnetic field (TMF) contacts contain radial components and tangential components in the TMF generated when the current is interrupted. The tangential force generated by the radial magnetic field component drives the vacuum arc to rotate, and the tangential magnetic field component generates a radial force that causes the vacuum arc to move radially outward. In this paper, in order to study the influence of the arc force direction on the arc characteristics, the influence of the contact structure parameters such as the inclination of the inner wall on the arc force direction is simulated, and the breaking tests of different levels of current are carried out on the contact with different structure parameters. It is found that the direction of the Lorentz force has a significant effect on the breaking characteristics of the current, and the tangential and radial force components have varying degrees of influence on the motion characteristics of the arc during the start process and the metal droplet splashing.

Safe stroke of vacuum breaking process in DC circuit breaker commutated by intermediate frequency current

The safe stroke between contacts of vacuum switch is the key parameter that can withstand transient recovery voltage (TRV) after arc extinction. In order to determine the minimum safe stroke during direct current (DC) interruption, this paper starts with the characteristic analysis of the commutation process. After breaking current zero crossing, contact gap is used to correlate the dielectric recovery level with TRV. In terms of theoretical description, based on the sheath development analysis of continuous transition model (CTM), different commutation moments and frequency have a perceptible effect on the TRV and dielectric recovery process. The breaking test of DC synthesis circuit with dual power supply is used to further verify the dielectric recovery level of vacuum gap, and the minimum safe stroke corresponding to reliable interruption. Simulation and experimental results show that safe stroke increases with the higher breaking current, TRV and its change rate during the DC breaking process, the corresponding commutation moment should be delayed. Finally, the influence of arc appearance on the safe stroke is discussed by analyzing the arc image of the draw-arc process. The safe stroke is helpful to determine the time setting for commutation moment and reliable breaking process of DC vacuum circuit breaker.

Sequential Mechanical Fault Diagnosis in High Voltage Circuit Breaker using Attention Mechanism

To address the shortcomings of traditional shallow-based model in terms of feature extraction and generalization capacity, this paper provides a high-voltage circuit breaker mechanical condition online detection scheme by using attention mechanism to locally weight the sample correlation and combining convolutional neural network (CNN) and long short-term memory (LSTM) network. The network uses convolutional layers for feature transformation of the raw vibration data, combined with the local time-domain feature representation capability of the gated unit, to extract fault-sensitive features. The temporal deep learning model using the attention mechanism enables it to extract global features of long-time sequences while making important features obtain higher weight parameters. The resulting model improves the overall learning and recognition efficiency. The experiments on the vacuum circuit breaker show that the proposed model has better performance than the classical diagnostic method based on the support vector machine.

Development and Testing of a 252 kV/2500 A-40 kA Multi-Break Bus-Coupler Fast Vacuum Circuit Breaker

It is effective to open the bus-coupler circuit breaker in case of a short-circuit fault. A fast vacuum circuit breaker (FVCB) is an ideal bus-coupler circuit breaker due to its high velocity. The objective of this study was to develop and test a 252 kV/2500 A-40 kA multi-break bus-coupler FVCB. The 252 kV FVCB contained 12 FVCB units. Each phase consisted of four FVCB units connected in series. Each FVCB unit had an electromagnetic repulsion mechanism with an average opening velocity reaching 6.5 m/s. Test results showed the opening time was 1.11 ± 0.08 ms. The capacitance of the voltage grading capacitor of each break was determined to be 10 nF. The prototype 252 kV bus-coupler FVCB passed all partial test duties according to the IEC 62271-100: 2008 and IEC 62271-1: 2007 standards, which include an insulation test and a terminal fault test among others. A 252 kV/2500 A-40 kA multi-break bus-coupler FVCB can be used to quickly cut off a short-circuit fault and effectively limit a short-circuit current.

Voltage transient management for Alternating Current trains with vacuum circuit breakers

Alternating current power supplies and rolling stock with 25 kV (50 or 60 Hz) and 15 kV (16.7 Hz) traction systems do not have the characteristics and behaviour of a typical three-phase medium-voltage distribution system. Switching inductive loads with a vacuum circuit breaker (VCB) in MV traction systems poses familiar challenges as well as some unique challenges, such as the crossing of phase change neutral sections. Transformers represent highly inductive loads due to their iron core and, thus, the consequences of energizing and disconnecting a transformer and dealing with the energy stored in its inductance must be considered within a system context. The authors of this study consider two transient phenomena associated with switching single-phase, medium voltage, AC traction transformer loads using a VCB on railway rolling stock: (i) switching transients that occur when disconnecting a transformer, particularly if lightly loaded and (ii) pre-ignition and current inrush that occurs when energizing a transformer. Both phenomena can cause reliability problems, requiring increased system maintenance or resulting in premature failures of system components. The authors review the use of controlled switching and other state-of-the-art methods to prevent or limit voltage transients when switching a transformer load by means of a VCB. The effective application of such techniques has been demonstrated in previous research or established in practical applications by manufacturers and electrical distribution network companies.

REDUCTION OF ENERGY LOSSES ON HEATING OIL CIRCUIT BREAKERS 35–110 KV IN JSC «CHERNIGIVOBLENREGO»

The analysis of the state of 35–110 kV circuit breakers in the Chernihiv region, which are on the balance sheet of the operator of the distribution system JSC «Chernigivoblenergo», has been carried out. It was shown that the number of circuit breakers that satisfy regulatory documents is only 18.9 % in 35 kV and 2 % in 110 kV power networks. Unfortunately, most of the 35–110 kV circuit breakers in the Chernihiv region are low-oil and bulk-oil type, which required heating during cold meteorological conditions. The article assess the duration of the circuit breakers heating and their drives, depending on the selected set point of the temperature and the averaging interval of the ambient temperature, and the value of technological energy losses. The article considers following ways to reduce technological costs for heating: optimization of the heating control system, replacement of oil circuit breakers with modern vacuum and SF6 circuit breakers, which require lower costs on heating, and applied both above ways. The effectiveness of the above ways was done with apply Net Present Value, which includes not only investments and Net Profit Margin, but also operating costs and Discount Rates. It has been shown that all of the above ways are effective. In particular, the least costly is the modernization of the heating control system, which has payback period is low three years. The payback period for second way to replace all 35–110 kV oil circuit breakers with modern ones at JSC «Chernigivoblenrego» is about 6.5 years, but this way requires large investments. However, this way cannot be done in one year. Therefore effectiveness will be less due to energy losses to operated oil circuit breakers.

Research on measures suppressing high frequency transient overvoltage in offshore wind farms

A large number of different types of cables, wind turbines, transformers and vacuum circuit breakers (VCBs) are used in power collecting system of offshore wind farms (OWFs). Due to the phenomenon of traveling wave refraction and reflection in cable collector system, transient overvoltage with high amplitude and high steepness will be generated when reignition phenomenon occurs in frequent operation of vacuum circuit breakers on wind turbines, which will cause serious damage to transformers, the problem of overcurrent is also becoming more and more serious. Therefore, through the electromagnetic transient simulation software of ATP-EMTP, a single-phase model of VCB switching-off transformer in offshore wind farm is built to study the influence of the separation speed of contacts of vacuum circuit breaker, high-frequency arc quenching capability and arching time on overvoltage. Then, the medium voltage cable collector system of OWF is built. Installing ferrite ring near the VCB or on the high-voltage side of transformer can suppress high frequency transient overvoltage. The results show that the high frequency transient overvoltage generated by offshore wind farm can be well suppressed after the installation of overvoltage protection device.

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.

Influence of a Pulsed Axial Magnetic Field on a High-Current Arc of a Vacuum Circuit Breaker

Influence of a Pulsed Axial Magnetic Field on a High-Current Arc of a Vacuum Circuit Breaker

Excitation Temperature Imaging of Vacuum Arc Based on Two-Line Radiance Method

The excitation temperature of the high-current vacuum arc was measured based on the intensity ratio of two Cu I spectra of 510.6 and 515.3 nm. Diffuse mode vacuum arcs with the peak current of 2 kA, igniting between 5-mm gap, 10-mm phi electrodes, Cu100, Cu80Cr20, and Cu50Cr50 wt.% contacts were measured by a multiple-imaging optical system and high-speed video camera. It turns out that the excitation temperature was almost evenly distributed in the gap. The excitation temperature at the current peak depended on the electrode material and took higher in the order of Cu100, Cu80Cr20, and Cu50Cr50. The excitation temperature was also measured by a spectroscopic approach, and it showed the same tendencies as the measurement using multiple-imaging optical systems and a high-speed video camera. The current decreasing phase of dc interruption was simulated by using semiconductor switches at the peak of ac 50-Hz current, and as a result, the current zero with a decreasing ratio of 30 A/μs was realized. The excitation temperature for the Cu100 electrode decreased with the decreasing current, whereas those for Cu80Cr20 and Cu50Cr50 increased. This difference suggests that developing direct current vacuum circuit breakers needs the optimization of the electrode materials, current waveform, and plasma parameters in the gap.

Medium voltage vacuum circuit breaker with per phase electromagnetic actuator

In medium voltage vacuum circuit breakers, in order to achieve an even distribution of force along the entire length of the drive shaft, the drive mechanism is made per phase, that is, a separate electromagnet is installed under each pole. The analysis of designs and features of operation of vacuum circuit breakers with a per phase electromagnetic drive is carried out. Deficiencies in the designs of these drives have been identified. The design of a vacuum circuit breaker with a per phase electromagnetic drive and a kinematic diagram of the operation of a vacuum circuit breaker with a monostable polarized electromagnet and a return spring during the closing operation are considered. As a per phase drive, it is proposed to use three monostable polarized electromagnets with return springs, which makes it possible to reduce the overall dimensions of not only the drive electromagnet, but also the vacuum circuit breaker. Moreover, the return spring is not included in the design of the proposed electromagnet, but is part of the circuit breaker drive mechanism. The design of the housing of the vacuum circuit breaker with a per phase drive and a synchronizing shaft has been developed, which makes it impossible for the non-simultaneous closing and opening of the main contacts when performing switching operations. The calculation of a monostable polarized electromagnet is carried out and the possibility of its use as a per-phase drive in a medium voltage vacuum circuit breaker is confirmed.

Novel Design of 3-D Microstructure Contact Material Generating Autoexcitation Magnetic Field

The development of vacuum circuit breaker (VCB) toward large current and high voltage is extremely limited with contact material. Herein, a new type of VCB contact model including microstructure is proposed. Emerging contact material achieves the breakthrough from external applying to self-excited magnetic field, besides strong magnetic strength and low temperature rise. Three-dimensional finite-element simulations, which contain microcoil, unit groups, and coupled contacts, were implemented. And the influence factors involve eddy current losses, iron core diameter, units’ spacing, and copper–chromium layer thickness. Simulation results indicate that the magnetic field is the most efficient when the distance between the coupled coils is 1.65 mm and the thickness of the Cu–Cr layer is 3 mm. Moreover, the relative practical models and measures were carried out to verify the distribution of magnetic field, and the results were in good agreement with theoretical predictions. Therefore, the theoretical data can guide the design of practical contact models and support the optimization of structural parameters, applied to vacuum interrupter.

Topology, Modeling and Transient Current Transfer Analysis of DC Hybrid Vacuum Circuit Breaker Based on SiC Module

Topology, Modeling and Transient Current Transfer Analysis of DC Hybrid Vacuum Circuit Breaker Based on SiC Module

Experimental investigations on the post-arc current of the vacuum circuit breaker in an active mechanical DC circuit breaker

Vacuum circuit breakers (VCB) are commonly used in active mechanical direct current circuit breakers (DC CBs) to accomplish the interruption of the fault current. The post-arc current phenomenon of a VCB is related to the dielectric recovery process of the VCB. Thus, we performed experiments to investigate the influence on the post-arc current by taking the electrode separation, breaking current, and interruption of the bi-directional current with the injecting high frequency current in a fixed direction into account. To be in accordance with the practical interruption duty, the breaking current in the experiment ranges from 500 A to 20 kA. At the same time, the di/dt at current zero (CZ) varies between 200 and 1100 A/μs. The experiment results reveal that the peak value of the post-arc current in an active DC circuit breaker can reach more than 100 A with high di/dt at CZ. It is found that with a longer electrode separation, not only the residual charge increases but also the post-arc current increases. The arcing current before CZ can influence the post-arc current but the effective duration before CZ is short. This duration is the memory time and it is derived from the experiment results. The influence of the breaking current and interruption of the bi-directional current with the injecting current in a fixed direction are dependent on the relation of the current commutation time with the memory time.

Optimizing the Opening Velocity for a Vacuum Circuit Breaker With Cup-Type Axial Magnetic Field Contacts

This article extends the quantitative method of optimizing the opening velocities for a vacuum circuit breaker (VCB) with cup-type axial magnetic field (AMF) contacts. The material of the AMF contact is Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> Cr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> . We define v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> as the initial opening velocity over half the full contact gap and v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> as the average velocity over the full contact gap of 20 mm. We optimize v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> using the transition of anode-discharging modes, of which we combine the footpoint mode and anode spot mode into a large-gap high-current (LGHC) mode. The experiment shows that v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> should be higher than a threshold velocity v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1_th</sub> , which corresponds to a peak critical contact gap d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1_th</sub> for the transitions of an intense arc mode into a diffuse arc mode, in high-current interruption. The higher v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> is than v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1_th</sub> , the faster the intense arc mode evolves into the diffuse arc mode. This helps successfully interrupt the short-circuit current in a short arcing time. Another threshold velocity, v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2_th</sub> , corresponds to the maximum critical contact d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">II_th</sub> for the formation of an LGHC mode in the second arc current half-wave. A high v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> design needs v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> to be lower than v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2_th</sub> . The lower v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is than v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2_th</sub> , the better the VCB avoids the LGHC mode in high-current interruption. This helps interruption over a long arcing time. We propose an intelligent opening and breaking operation for VCBs with cup-type AMF contacts, whereby the VCB opens with different opening velocities according to the short-circuit current level.

Development and Fault Prediction of a New Operating Mechanism of HTPPM

In this article, we take a 126 kV single-break vacuum circuit breaker as the research object and study the application of high-energy-density PM motor in the high-voltage circuit breaker for the first time. The PM motor maintains maximum power density and torque density during the start-up phase. Note that most of the faults of high-voltage circuit breakers are mechanical faults. We designed a set of mechanical fault prediction systems for high-voltage circuit breakers. We present the prediction method of the opening and closing action curve of the high-voltage circuit breaker. It is inspired by Chaos Ant Colony Algorithm (CAS) and an optimized Long- and Short-Term Memory (LSTM) cycle neural network. We constructed the main structure of the neural network expert system and established the fault prediction model of the high-voltage circuit breaker, based on the LSTM cycle neural network, optimized by CAS. We used the improved least-square method to achieve the operation accuracy of the phase control switch. Finally, we completed the development and experiment of the prototype.