Hybrid Phase-controlled Circuit Breaker with Switch System Used in the Railway Auto-passing Neutral Section with an Electric Load

Constrained by the characteristics of neutral sec- tions (NS) and traditional vacuum circuit breakers, previous phase-controlled strategies have a long power supply dead time, it is difficult to realize a continuous power supply to the auxiliary power system. The dead time can be reduced by using the ground automatic convert method, hybrid phase-controlled technologies can in theory completely eliminate inrush currents. In this paper, a new system based on hybrid phase-controlled switches is described and termed ground-switching passing neutral section system (GPNSS). The principle for restraining inrush currents is analyzed and strategies are carried out with the dead time limited to 5 ms. The characteristics of the vacuum circuit breaker are illustrated and the closing time window of the transformer is quantified. Through the use of mechanical switches and power electronics, the auxiliary power system may be continuously pow- ered. The prototype system is implemented and experimentally tested in the laboratory.

Development and Tests of ZW-126/D2000-40 Vacuum Circuit Breakers with Controlled Switching Technology

A ZW-126/D2000-40 type single-break vacuum circuit breaker(VCB)with controlled switching technology is designed and produced in this paper.The results of type tests based on IEC and GB standards are presented.A 126 kV singlebreak vacuum interrupter(VI)with 3/4 coil axial magnetic field(AMF)contacts is used in the VCB,which can interrupt short currents of 40 kA.The external insulation of the VI is provided by SF_(6) at 0.1 MPa.In order to match the 126 kV single-break VI and controlled switching device,a long-stroke electro-magnetic force actuator(EMFA)with 16 kN closing holding force and 3.5 m/s average opening speed is designed.Moreover,a position tracking controlled switching device based on closed-loop control using the technology of a fuzzy control algorithm and pulse width modulation is applied to the controlled switching device.This device is applied to control the coil current of EMFA and the electromagnetic force,so as to control the EMFA to follow the ideal position curve.The type tests of 126 kV VCB are all passed according to the IEC62271-100 and GB1984-2014,including dielectric tests,basic short-circuit tests,shortline fault tests,out-of-phase tests,etc.The strong capacitive current breaking capacity and mechanical strength of the VCB are proved by the capacitive current switching test of class C2,electrical endurance test of class E2 and mechanical endurance test of class M2.The electromagnetic compatibility(EMC)tests are passed according to the IEC61000-4.The controlled switching test of capacitive current was successful according to IEC62271-302 and GB/T30846-2014,and the controlled switching accuracy is less than±0.5 ms.The test results show that the VCB has excellent performance,which has broad application prospects in special occasions at a 126 kV voltage level,such as a switching capacitor and no-load transformer,etc.

Closing performances of double-gap laser-triggered vacuum switch

To develop high-voltage-pulsed power switches with better performances,a multi-gap laser-triggered vacuum switch is proposed in this study.Based on established test pro-totype for double-gap laser-triggered vacuum switch,closing processes of double-gap laser-triggered vacuum switch are discussed combined with laser-produced plasma.Closing performances of double-gap laser-triggered vacuum switch under different gap polarity configurations,operating voltages,laser energies and laser split ratios are inves-tigated.Closing time delay characteristics of double-gap laser-triggered vacuum switch and single-gap laser-triggered vacuum switch are compared later.The test results prove that,affected by the imbalanced developed initial plasma between gaps,double-gap laser-triggered vacuum switch with two positive gaps and 1:1 laser split ratio presents best closing performances than other switches.With the rise of laser energy,closing delay time and jitter time of double-gap laser-triggered vacuum switch both decrease,while the influences from increasing voltages are weak.Closing delay time of P-P type double-gap laser-triggered vacuum switch can be controlled within 103�1.5 ns under 90 mJ laser energy,and it is about 10 ns longer than single-gap laser-triggered vacuum switch.For some direct current applications with changing voltage directions,P-N type double-gap laser-triggered vacuum switch with 1:1 laser split ratio shows more stable closing per-formances.In addition,closing performances of double-gap laser-triggered vacuum switch can be further improved by optimizing the developments of initial plasma in series gaps.