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The paper focuses on the vacuum arc commutating characteristic which is a common basic problem in resistive fault current limiters. The current commutating characteristic of the current can be diverted into the current limiting resistor from the vacuum circuit breaker is mainly researched. The influence of the current amplitude, the current limiting resistor resistance, the arcing time, the transverse magnetic field and the current frequency on the time of the current commutation and the current in the moment of the completion transition is investigated and analyzed. According to the experimental results, the mathematical description of the vacuum arc commutating characteristic is obtained. The interaction between the vacuum arc and the transverse magnetic field is discussed. The paper provides the foundation for the structure and parameters optimization of the resistive fault current limiter. [ABSTRACT FROM AUTHOR]

At present, multibreak vacuum circuit breakers (VCBs) have attracted more attention in order to meet the requirement of the environmental protection, high-voltage VCBs, capacitive current switch-off, and the dc current breaking. The advantages and disadvantages of multibreak VCBs are analyzed and discussed according to the research status. Then, the synergy effect of multibreak VCBs is proposed, which is the interaction among the arc memory, current zero characteristic, and the postarc characteristic. The target of the synergy effect is the synergy between the dynamic dielectric recovery strength and the postarc dynamic voltage distribution. The maximum breaking capacity can be obtained in the above-mentioned synergy control. Finally, the optimization design, key technology, basic theory, and application of multibreak VCBs are discussed. With the development of multibreak VCBs, it will be widely used in high-voltage level, HVdc, and pulsed-power switchgear in the future. [ABSTRACT FROM AUTHOR]

This paper proposes the equivalent circuit of postarc dynamic voltage distribution (PDVD) in multibreak vacuum circuit breakers (VCBs). The equivalent circuit is composed of controlled postarc sources, postarc resistors, and equivalent capacitors. The sheath growth and the postarc process of double-break VCBs are analyzed. The PDVD is divided into four processes: the initial transient recovery voltage (TRV) process, the oscillating TRV process, the stable TRV process, and the power-frequency voltage process, which can be analyzed by the equivalent circuit. The novel equivalent circuit of the PDVD in multibreak VCBs is gained by introducing the controlled postarc current source. The test platform is set up in the synthetic circuit. The postarc current, grading capacitor current, and the TRV are measured to analyze the PDVD in the above four processes. The test results verify the theoretical analysis. Therefore, the mechanism of the PDVD in multibreak VCBs is obtained and described by the equivalent circuit, which is useful to gain even voltage distribution and improve the breaking capacity of multibreak VCBs. [ABSTRACT FROM AUTHOR]

When double‐break vacuum circuit breakers (VCBs) interrupt the fault current, the series arc will generate their individual magnetic fields in different breaks. The magnetic field in one break will influence the arc in another break if the magnetic field is strong enough or the two breaks are very close. In this case, an interactive magnetic field effect happens. This field is also called the bias magnetic field (BMF). BMF can cause anode erosion and affect the performance at current zero. The distribution of BMF and the optimal configuration of the double‐break VCBs were obtained by the electromagnetic field simulation using the Ansoft Maxwell software. Based on the simulated magnetic field data, in the experiments, the interaction between the series vacuum arcs in double‐break VCBs was equivalent to the interaction between a single vacuum arc and the magnetic field generated by a Helmholtz coil. A high‐speed CMOS camera was used to record the trajectory of the vacuum arc plasma under different BMFs with different types of contacts. The results show the BMF can increase the arc voltage, and the arc becomes unstable. When the BMF becomes stronger, the arc voltage increases, and the arc becomes more unstable. In addition, for different types of contacts, the development process of the arc and the influence level are different under the same BMF. For a Wan‐type transverse magnetic field (TMF) contact or strong BMF, metal sputtering is evident and anode erosion becomes serious. For a cup‐type axial magnetic field (AMF) contact, the influence of BMF on the series arc plasma in double‐break VCBs is less than that of the Wan‐type TMF contact. The results of this work may be helpful for the design of compact double‐break VCBs. [ABSTRACT FROM AUTHOR]

In order to reveal the mechanism of the residual magnetic field in vacuum interrupters (VIs), the vacuum arcs and the postarc characteristic with external AMF at current zero are investigated. The magnetic field of the 10-kV/20-kA VIs is analyzed. And then, the phase shift and the residual AMF are obtained. The test platform is established in the synthetic test circuit. The pulsed AMF is applied at current zero with the pulsewidth of 4 ms, and the magnitude can be adjusted from 0 to 200 mT. The transparency VIs with external AMF at current zero is observed by the high-speed CMOS camera to analyse the vacuum arcs development. The postarc current and transient recovery voltage are measured by the postarc current measuring equipment and the voltage divider so that the postarc characteristic such as postarc current and postarc charge can be obtained. The influence of the pulsed AMF at current zero on the vacuum arc development and postarc characteristic is gained and the mechanism of the AMF at current zero is analyzed, which can be useful to special AMF contact design for different applications. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of the pulsed AMF arc control on the vacuum arc and the post arc characteristic to reveal the mechanism of AMF arc control in different control time and find the proper AMF arc control. The pulsed AMF control system is designed and the pulse width is adjusted from 1.5 ms to 10 ms by changing the capacitors. The test circuit is set up in the synthetic test circuit and the test vacuum interrupter (VI) is transparent in order to observe the development of the vacuum arc by the high speed CMOS camera. The rated voltage and current of the test VI is 10 kV and 25 kA respectively. The post arc current of the test VI is measured in order to analyze the post arc characteristic, such as the post arc charge, post arc conductance and dynamic dielectric strength. The development of vacuum arc and the post arc characteristic influenced by the pulse width, magnitude and control time of the pulsed AMF is obtained, which is useful to special magnetic contacts design. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic dielectric recovery synergy (DDRS) of hybrid circuit breakers (HCBs) with CO2 gas and vacuum gaps in series. The interaction between the vacuum arc and CO2 gas arc is simulated by the continuous transient arc model and Mayr arc model. The simulation results indicate that the extra methods, for example, dividing capacitors, are needed to obtain optimal DDRS of HCB. The prototype of HCB and the test circuit are established. The influence of the coordination of arcing time, dividing capacitors, and the CO2 gas pressures on the transient recovery voltage (TRV) distribution and the breaking capacity is investigated. The differences of HCBs with SF6 gas and CO2 gas are also compared. According to the results, favorable DDRS in HCB can be obtained in the condition that the vacuum gap endures the initial TRV while the following major TRV distribution is mainly depended on the dynamic dielectric in CO2 gas gap. However, the dynamic dielectric recovery of CO2 gas gap is limited by the structure of rotating arc CO2 gas interrupter in this paper. In the future, the interruption capacity of HCB based on CO2 gas can be improved by synergy control, as the development of CO2 gas circuit breakers. [ABSTRACT FROM PUBLISHER]

The current-zero characteristic of vacuum circuit breakers (VCBs) has an important influence on the dynamic dielectric recovery and the success of the breaking test. In the paper, the characteristic of the post-arc current, post-arc charge and the post-arc conductance at current-zero is researched to obtain the influence of the arc memory on the current-zero characteristic and the post-arc characteristic. Based on the synthetic test circuit, the test plat of the current-zero characteristic is set up and the test VCB is a transparency vacuum interrupter in order to observe the development and extinguishing process of the vacuum arc by the high speed CMOS camera. The distribution law of post-arc characteristic is gained by measuring and processing the post-arc current. The relationship between the post arc charge and the final position of last cathode spot is investigated. The current-zero characteristic of VCBs supply the base for controlling vacuum arc, improving the breaking capacity, which maybe also useful to VCBs with multi-break. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of the axial magnetic field (AMF) arc control on voltage distribution (VD) of double-break vacuum circuit breakers (VCBs) in order to gain balanced VD, and thus enhance the breaking capacity. The interaction of vacuum arc plasma, postarc current (PAC), and AMF is discussed. We conduct the breaking test of double-break VCBs with externally applied AMF of a different pulsewidth, magnitude, and a different moment. The PAC, postarc charge, and the VD are measured to analyze the relationship between the AMF arc control and the VD. The optimal AMF arc control and the relationship between the AMF magnitude and the unbalanced voltage ratio are gained when the grading capacitors were 400 pF. The experimental test showed that the proper AMF arc control can improve the unbalanced VD. The mechanism is that the proper AMF arc control can make the postarc charge small and stable, so the unbalanced postarc charge, which caused the unbalanced VD is limited. [ABSTRACT FROM AUTHOR]

In order to find the synergy of double-break vacuum circuit breakers (VCBs), we conducted a synthetic test including different vacuum gaps, different type electrodes, and different grading capacitors. The double-break VCBs are composed of Axial Magnetic Field (AMF) and Transverse Magnetic Field (TMF) contact VCBs, which can constitute four combinations. The optimal combination of AMF and TMF type electrodes was obtained by comparing with the breaking capacity and voltage distribution of the four combinations. The breaking capacity of double-break VCB with AMF and TMF type electrodes in series while the AMF interrupter is on the lower side is largest because the voltage distribution is the most even which is caused by the different equivalent capacitances of different interrupters. The optimal matching vacuum gaps of the best combination were obtained by a synthetic test of different vacuum gaps, which may make the grading capacitors of double-break VCBs small, even obsolete. The combination of maximum breaking capacity was series AMF type interrupters with suitable grading capacitors of 500–2000 pF. The experimental results provide the best combination and matching control mode for VCBs with double-break. [ABSTRACT FROM PUBLISHER]

In tank-type multi-break vacuum circuit breakers (VCBs) and gas-insulated switchgear (GIS), the non-uniform distribution of vapor shield potential in the vacuum interrupters impacts the post-arc process significantly. To explore the effect of the vapor shield potential on the development of the post-arc sheath, a particle-in-cell model with shield potential control is proposed to obtain two-dimensional distributions of post-arc particles. Based on the synthetic test circuit and probe array, the test platform of the post-arc characteristic diagnostic is set up to verify the influence of vapor shield potential distribution on the post-arc sheath. The extinguishing process of the vacuum arc is also observed by the high-speed CMOS camera. Simulation and experimental results show that at shield potential of 0.5 transient recovery voltage, the post-arc sheath develops most rapidly and the distribution of cathode spots is the most uniform. These findings can provide valuable insights for the design of vacuum interrupters and the control of shield potential in tank-type GIS. • A new structure of series special self-voltage sharing vacuum interrupters in tank-type circuit breakers or gas insulated switchgear is proposed. • A PIC simulation model for the post-arc sheath development in the vapor shield potential control of vacuum interrupters is established. • A probe diagnostic approach is employed to analyze the decay process of post-arc residual plasma in vacuum interrupters. • The vapor shield potential affects the development process of the post-arc sheath, with the best effect observed when the shield potential is at 0.5 TRV. [ABSTRACT FROM AUTHOR]

• An environment-friendly vacuum circuit breaker was proposed to replace SF 6 breakers. • Multi-physical field simulation was operated to gain temperature distribution. • An optimal method with evolutionary algorithm was carried out for structural design. Environment-friendly live tank multi-break vacuum circuit breaker (MBVCBs) is a future direction of high voltage gas insulated switchgear (GIS). The temperature field distributions are extremely important to guarantee the reliable operation of live tank MBVCBs. However, the thermal performance of live tank MBVCBs is not studied in detail, and the structural design is usually restricted to inadequate variations. Therefore, this paper investigates the temperature distribution of environment-friendly live tank MBVCBs through electromagnetic-thermal-flow field coupling simulation at first. Based on the simulation results, the influence of structural parameters on temperature distribution is analyzed. Then, a mathematical relationship between the structural parameters and the maximum temperature of live tank MBVCBs is established by Back-Propagation (BP) neural network, which could provide a large amount of data and be the objective function in multi-objective optimization. Finally, the modified particles swarm optimization (PSO) approach with adaptive dynamic weight is proposed to make trade-off between the maximum temperature and the material cost. The results show that the material cost is reduced by 19.5% under the temperature requirement of IEC 62,271–1 standard and GB/T 11,022 standard. The optimization method could be very helpful in optimization of live tank MBVCBs or GIS design. [ABSTRACT FROM AUTHOR]