Guowei Ge

Experimental Investigation Into the Synergy of Vacuum Circuit Breaker With Double-Break

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.

Experimental investigation on the matching characteristics of vacuum circuit breaker with double-break

In the paper, the prototype of vacuum circuit breaker with double-breaker was set up. In order to find the matching characteristics of VCB with double-break by means of breaking test, the matching characteristics test includes different vacuum gaps, different type electrodes and different grading capacitors. The optimal combination of AMF and TMF type electrodes was gained 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 in lower side is largest because the voltage distribution is most even caused by the different equivalent capacitance of different interrupters. The optimal matching vacuum gaps of the best combination were got by matching characteristics test of different vacuum gaps. The combination of maximum breaking capacity was series AMF type electrodes with suitable grading capacitors. According to the voltage distribution and breaking capacity, the appropriate range of grading capacitors is from 500pF to 2000pF. Moreover, the influence of grading capacitors was discussed by detecting the current of grading capacitors. The research was useful to series VCBs witch replacing SF6 circuit breaker to apply in high voltage level.

Influence of the AMF Arc Control on Voltage Distribution of Double-Break VCBs

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.

Post-arc current measurement based on current transfer characteristic

The paper proposes a novel post-arc current measuring equipment (PACME), which is composed of vacuum switch, transfer resistance, protective gap and high-precision current sensor. The principle of the measurement is based on current transfer characteristic between the vacuum switch and transfer resistance. The current-transfer model of the post-arc current measurement is established to gain the characteristic of vacuum arc conductance and the completion time of current transfer influenced by the transfer resistance, current of main circuit and the contacts opening time. The vacuum arc of PACME extinguished just before the main current approach zero while the main current is completely transferred to the transfer resistance. According to the simulation result, the PACME is designed, especially; the transfer resistance is non inductive and over current protection. The post-arc current of vacuum switch with axial magnetic field (AMF) and transverse magnetic field (TMF) contacts was measured in synthetic short-circuit test. The measuring result of post-arc current is accurate and small interference, which satisfied the post-arc current measurement of vacuum circuit breakers.

Investigation on the Vacuum Arc Commutating Characteristic With Application to Postarc Current Measure

This paper focuses on the vacuum arc commutating characteristic (VACC) between the parallel-connected vacuum arc and the shunt resistor, which is the base of the postarc current (PAC) measure. The test platform is established in the synthetic test circuit. The influence of the current magnitude, shunt resistor, arcing time and current frequency on time of the current commutation and the current in the moment of the completion transition is investigated. The mathematic description of the VACC is obtained, which is useful to parameter design of the PAC measure. The PAC of 10-kV vacuum circuit breakers is measured in synthetic test circuit. The photos of the vacuum arc and the waveform of the current commutation are gained to verify the success of the commutation. In conclusion, the VACC is gained and applied to measure the PAC.

A novel post-arc current measuring equipment based on vacuum commutation and arc blow

The paper proposes a novel post-arc current measuring equipment (PACME), which is based on the vacuum arc commutation and the arc blow. The PACME is composed of vacuum circuit breaker (VCB), shunt resistor, protective gap, high-precision current sensor and applied transverse magnetic field (TMF). The construct and parameters of the PACME is designed. The vacuum arc commutation between the vacuum arc and the shunt resistor is investigated and the influence of the TMF arc blow on the vacuum arc commutation is discussed. The test platform is established in the synthetic short-circuit test. The high-speed CMOS camera is used to observe the development of the vacuum arc in the current commutating process. The protective characteristic of the PACME is test and the post arc current of the AMF contact VCBs is measured. The measuring result of post-arc current is accurate and small interference and the post arc charge is obtained. The experimental results verifies that the PACME is correct and accurate, which can be used to measure the post arc characteristic in interrupting test.

Simulation and experimental research on series vacuum arc of vacuum circuit breaker with double-break

The paper established the simulation model of series vacuum arc of Vacuum Circuit Breaker (VCB) with double-break using Magneto Hydro Dynamic (MHD) model. To gain the matching characteristics of series vacuum arc, the influence of series different vacuum gaps and interactional magnetic field was analyzed. The distribution of micro-characteristics was depended on the axial magnetic field causing by different vacuum gaps while the interactional magnetic field between series vacuum gaps was negligible. The research platform of series vacuum arc of VCB with double-break based on transparent vitreous vacuum interrupters was set up. The series vacuum arc was simultaneously acquired by two CMOS high-speed cameras. The out of sync of series vacuum arc extinguishing which was arisen when the VCB with double-break asynchronously opening was proved by arc voltage, arc images and arc area change. With the asynchrony increasing, the probability of out of sync of series vacuum arc extinguishing enhanced. The arc extinguishing of late opening vacuum interrupter was earlier than the early, which was explained by the distribution of micro-characteristic from the simulation. The experimental result and simulation result provided the basis for the practical application.

HVDC hybrid circuit breaker based on SF6 interrupter and vacuum interrupter in series

The hybrid circuit breaker (HCB) which consists of SF6 interrupter (GI) and vacuum interrupter (VI) connected in series has been put forward to be applied in HVDC system. The paper analyses the theoretical basis of HCB and designed the implement plan. Vacuum has the rapid dielectric strength recovery speed which has the advantage of interrupting high frequency current while SF6 has the dielectric strength. The current zero was easily achieved by driven-oscillation because of the superior negative resistance characteristic of SF6. After current post zero, VI endures initial transient recovery voltage and GI undertakes most of the recovery voltage which is achieved by the nonlinear resistor and the dividing capacitor connected in parallel with the VI and GI respectively. The optimum matching parameters was gained through the simulation of HCB. The simulation results of static voltage distribution and transient recovery voltage distribution verified the analytical model. The result provided the basis for further studying of HCB interruption.

Research on influence of the magnetic arc blow in multi-break vacuum circuit breakers

The paper aims to investigate the influence of the interactive magnetic field in multi-break vacuum circuit breakers (VCBs) on the arc plasma and the post-arc characteristic. The magnetic field of multi-break VCBs is asymmetric and off-center because of the interactive magnetic field, which can be called bias magnetic field (BMF). The BMF distribution of double-break VCBs is gained by electromagnetic analysis. The test circuit of the magnetic arc blow in multi-break VCBs is established by simplifying as the interaction between the vacuum arc and the BMF. The influence of the magnetic arc blow on the arc plasma is studied by the high-speed CMOS while the relationship between the post-arc dynamic dielectric recovery and the magnetic arc blow is obtained by the measurement of the post-arc current. The results indicate that the influence of the magnetic arc blow on the vacuum arc and post-arc dynamic dielectric recovery with TMF contacts is larger than that of AMF contacts. The vacuum arc with TMF contacts bends to the opposite direction of Ampere force when the BMF is below 100mT and the post-arc charge obviously varies from 9μC to 50μC. Therefore, the paper can provide the base of construct and configuration to avoid the influence of the magnetic arc blow.

The arc model Simulation of vacuum switch with triple-break

The dynamic voltage distribution ratio and operation synchronism of vacuum switch with multi-breaker is the key determinant of the success interruption. Based on the transient equivalent model of vacuum switch with triple-break, the article analyzed equivalent capacity and voltage distribution ratio in different gap. The continuous transition model of vacuum switch with multi-breaker which described the interruption process of the arc in vacuum was set up. The dynamic simulation of vacuum switch with triple-break was implemented in the Transient Analysis of Control Systems (TACS) within ATP to simulate the influence of the diverse voltage distribution ratio and operation synchronisms to breaking capacity. From the simulation, the maximum range of operation synchronisms and the permissible maximum deviation of grading capacitors with little effect to breaking capacity were obtained. The result provided the theory basis for choosing the control accuracy and velocity characteristics of operating mechanisms and the magnitude and economy of grading capacitors.