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Geng Y.,Xi'an Jiaotong University | Chen Y.,Motic Xiamen Electrical Group Co. | Sun C.,Xi'an Jiaotong University | Yan J.,Xi'an Jiaotong University | And 3 more authors.
Gaoya Dianqi/High Voltage Apparatus | Year: 2016

Restrike during interrupting capacitor banks with vacuum circuit breakers may lead to severe switching overvoltage. Reducing the probability of restrike during capacitive current breaking is the ultimate solution to suppress overvoltage. In this paper, a new design of vacuum circuit breaker with a very low probability of restrike was proposed based on the analysis of restrike mechanism. A two-break vacuum circuit breaker was presented to carry out the duty of capacitor bank switching, and further meet the requirement of power system. A capacitive current switching test circuit has been designed, which consists of a high frequency inrush current circuit and a power frequency circuit, to perform back-to-back capacitor banks switching test. The test result shows that two-break vacuum circuit breakers can reduce the probability of restrike significantly. Short-circuit making and breaking capacity of the vacuum circuit breaker was validated by synthetic test. The optimum value of the shunt grading capacitor is 400 pF to ensure the stress of each break is approximately equal. So the design scheme of 40.5 kV two-break vacuum circuit breaker for switching capacitor banks is completely feasible. © 2016, Xi'an High Voltage Apparatus Research Institute Co., Ltd. All right reserved.


Tang W.,Motic Xiamen Electrical Group Co. | Zhang J.,Motic Xiamen Electrical Group Co. | Wang Z.,Motic Xiamen Electrical Group Co. | Wang Y.,Xi'an High Voltage Apparatus Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2014

In electrical property test for the different kinds of insulators, it is found that partial discharge of the insulator with specific structure will increase with the increase of storage time. We refer to this phenomenon as the hysteresis characteristic of partial discharge. After the combination of 3D simulation and validation tests, it is confirmed that the main reason of this phenomenon results from micro cracks or gaps occurred in the interface between insulating feet and epoxy resin material in later storage or service. By removing insulating feet, the interface between different materials is eliminated and the internal stress is decreased, so the improvements have been achieved. ©, 2014, Xi'an High Voltage Apparatus Research Institute. All right reserved.


Tang W.,Motic Xiamen Electrical Group Co. | Zhang J.,Motic Xiamen Electrical Group Co. | Wang Z.,Motic Xiamen Electrical Group Co. | Hong P.,Motic Xiamen Electrical Group Co. | Wang Y.,Xi'an High Voltage Apparatus Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2014

Solid insulated switchgear has been paid more and more attention by switchgear manufacturers. But we found that during actual manufacturing and testing process of epoxy resin casting insulator, the original electric field distribution of insulator is changed greatly due to metal-coating on outer surface of casting insulator and then results in many problems about electrical performance, such as partial discharge like needle discharge resulting from metal-coating terminal on inlet or outlet bushing insulator, is a typical and popular phenomenon. According to previous rich manufacturing and testing experience about solid insulated switchgear, combined with 3-D FEM simulation analysis, there have been solutions proposed, such as addition of shielding net without changing metal coating terminal location, addition of shed with changing metal-coating terminal location and addition of shed with groove and changing metal-coating terminal location. These proposed solutions proved by practical results are effective and feasible. ©, 2014, Xi'an High Voltage Apparatus Research Institute. All right reserved.


Tan X.,Chang'an University | Song Z.,Northwest University, China | Wang Z.,Motic Xiamen Electrical Group Co.
Instrumentation Science and Technology | Year: 2015

The interaction of bovine serum albumin with doxycycline was investigated using chemiluminescence and molecular docking. Doxycycline at concentrations from 1.0 to 2.5 × 103 pmol · L−1 quenched the chemiluminescence from the luminol–bovine serum albumin system. The data were analyzed using a chemiluminescence mathematic model for protein–ligand interaction, log[(I0 – I)/I] = logK + nlog[D]. The binding constant of bovine serum albumin with doxycycline was 3.36 × 105 L · mol−1 at 298 K with one binding site. The binding constant, enthalpy change, entropy change, and binding free energy change showed that the bonding of doxycycline to bovine serum albumin was spontaneous and enthalpy driven via hydrogen bonding and van der Waals forces. Further molecular docking analysis substantiated that doxycycline was well positioned in the pocket at the subdomain IIA (site I) of bovine serum albumin with a binding constant of 3.31 × 105 L · mol−1. Doxycycline served as both a hydrogen acceptor and donor and mainly interacted with the Arg217 residue through four hydrogen bonds with an average length of 2.55 Å. The chemiluminescence mechanism of doxycycline on luminol–bovine serum albumin system was evaluated, showing that a ternary complex of luminol–bovine serum albumin–doxycycline was formed with luminol and doxycycline at sites III and I of bovine serum albumin. 2016 Copyright © Taylor & Francis Group, LLC

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