Effect of profile and size of isolation trench on the optical and electrical performance of GaN-based high-voltage LEDs

2016 ◽  
Vol 366 ◽  
pp. 299-303 ◽  
Author(s):  
Shengjun Zhou ◽  
Chenju Zheng ◽  
Jiajiang Lv ◽  
Yingce Liu ◽  
Shu Yuan ◽  
...  
Keyword(s):  
High Voltage ◽  
Electrical Performance

Dynamic Interaction of High-Voltage Power Transformer Bushings, Turrets, and Tanks

2018 ◽  
Vol 34 (1) ◽  
pp. 397-421 ◽  
Author(s):  
Guo-Liang Ma ◽  
Qiang Xie ◽  
Andrew Whittaker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Voltage ◽  
Power Transformer ◽  
Bending Moment ◽  
Dynamic Interaction ◽  
Electrical Performance ◽  
Element Analysis ◽  
Ground Shaking ◽  
Input Motion

High-voltage (HV) bushings are attached to a power transformer tank either directly or indirectly via turrets. Turrets are used to achieve electrical performance requirements, but their potential impact on the seismic performance of the supported bushings has not been considered. Earthquake simulator testing and finite-element analysis were used to quantify the amplification of ground shaking through tanks (220- and 500-kV) and turrets to the points of attachment of roof- and sidewall-supported bushings. Substantial amplification of motion was seen in both physical experiments and numerical simulations. Sample bracing schemes external to the transformer tank were investigated to potentially reduce the motions experienced by the bushings. Bushing tip displacements were reduced in all stiffening cases studied, but the outcomes for bending moment at the bushing-turret connection were mixed, with no change in some cases and significant reductions in others. The physical and numerical studies described in this paper make clear the importance of dynamic interaction of bushings, turrets, and the power transformer tank. The methods currently used to address the amplification of input motion from the base of a tank to the points of attachment of its bushing are inadequate. The seismic design of HV power transformer tanks and turrets should be supported by finite-element analysis of validated models to avoid dynamic interaction in the bushing-turret-tank system, to minimize seismic demand on the transformer bushings, and to minimize the risk of substation damage in earthquakes.

scholarly journals Impact Transient Characteristics and Selection Method of Voltage Transformer Fuse

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 737
Author(s):  
Ke Wang ◽  
Hongwen Liu ◽  
Qing Yang ◽  
Lu Yin ◽  
Jisheng Huang
Keyword(s):  
High Voltage ◽  
Selection Method ◽  
Impact Testing ◽  
Electrical Performance ◽  
Voltage Transformer ◽  
X Ray ◽  
Electromagnetic Transient ◽  
Current Testing ◽  
Steady State Current ◽  
A Current

In a neutral ungrounded system, the high voltage fuses used to protect voltage transformers (VTs) often abnormally blow out, causing unbalanced VT operation. Fuses also fail to blow out in time, resulting in further damage to the VT. This paper reported the results of steady-state current testing, breaking characteristics, X-ray measurements, fuse corona testing, and electromagnetic transient impact testing for VT fuses. This paper comprehensively examines and analyzes the quality and electrical performance of VT fuses and provides new guidance for the use of high voltage fuses in voltage transformers. This paper recommends that 35 and 10 kV systems use fuses rated for a current of 1 A based on a single fuse, which is not easily oxidized and has a wound skeleton composed of an Ag or Ni melt.

Improvement in Electrical Performance of Schottky Contacts for High-Voltage Diode

2005 ◽  
Vol 483-485 ◽  
pp. 721-724 ◽  
Author(s):  
Tomonori Nakamura ◽  
Toshiyuki Miyanagi ◽  
Hidekazu Tsuchida ◽  
Isaho Kamata ◽  
Tamotsu Jikimoto ◽  
...  
Keyword(s):  
High Temperature ◽  
Schottky Barrier ◽  
High Voltage ◽  
Ideality Factor ◽  
Schottky Barrier Height ◽  
Schottky Contacts ◽  
Electrical Performance ◽  
High Temperature Annealing ◽  
Excess Current ◽  
Blocking Voltage

We investigated the effect of high temperature annealing on the Schottky barrier height (Fb) and the ideality factor (n-factor) of a Mo contact. In a Mo contact, the Fb increased and the leakage current decreased by annealing at 600oC, while no increase in n-factor and forward excess current owing to the high temperature annealing was observed. The Schottky barrier diode with Mo contact annealed at 600oC showed a blocking-voltage (Vb) of 4.15 kV and a specific on resistance (Ron) of 9.07 mWcm2, achieving a high Vb 2/Ron value of 1898 MW/cm2.

Study on surface electrical performance of machinable ceramics for high voltage electro-vacuum insulation

2014 ◽  
Vol 33 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
Guo-Qiang Su ◽  
Yan Lang ◽  
Guan-Jun Zhang ◽  
Bai-Peng Song ◽  
Xin-Pei Ma
Keyword(s):  
High Voltage ◽  
Electrical Performance ◽  
Vacuum Insulation

scholarly journals The effect of insulator geometrical profile on electric field distributions

2019 ◽  
Vol 14 (2) ◽  
pp. 618 ◽  
Author(s):  
Ali A. Salem ◽  
R. Abd-Rahman ◽  
M. S. Kamarudin ◽  
H. Ahmed ◽  
N.A. M. Jamail ◽  
...  
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Transmission Lines ◽  
Potential Distribution ◽  
Electrical Performance ◽  
Polluted Environment ◽  
Simulation Results ◽  
Electric Field Profile ◽  
Method Approach ◽  
Angle Width

<span>In recent years, silicone rubber (SIR) insulators are use widely on high voltage transmission lines, particularly in heavy polluted environment. The performance of SIR in highly dependent on electric field profile that may lead to other serious problem such as ageing and flashover phenomenon. In this paper, electric field and potential distribution around insulator profile were computed using finite element method approach. Insulator geometrical profile i.e. shed radius, inclination angle, width and length has been varied and analyzed. Simulation results reveal that electric field is greatest at area near to the ground and high voltage terminal. Several recommendations have been proposed on insulator profile in achieving optimized electrical performance of the insulator.</span>

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