scholarly journals Characteristics of the Partial Discharge in the Development of Conductive Particle-Initiated Flashover of a GIS Insulator

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2481 ◽  
Author(s):  
Junping Zhao ◽  
Zhengjie An ◽  
Bin Lv ◽  
Zhicheng Wu ◽  
Qiaogen Zhang

Conductive particles are one of the most important defects which can greatly degrade the performance of gas-insulated metal-enclosed switchgear (GIS). Many efforts have been made to clarify the influence on the withstand voltage, understand the flashover mechanism, and build a comprehensive model to describe the particle-initiated flashover. In this study, a partial discharge (PD) signal detected through a photomultiplier (PMT) and recorded by a high-speed data acquisition (DAQ) system was used to analyze the discharge development of a conductive particle-contaminated GIS insulator under constant high AC voltage. An additional PMT was used as a reference to eliminate the dark count of the PMT and the data collection method of a DAQ system was optimized to capture the pulse waveform of each PD to obtain detailed physical information. Spectra of the PD pulse amplitude over pulse width, PD counts within various amplitude ranges over time and phase resolved partial discharge (PRPD) patterns of the PDs in different stages are obtained through the captured PD waveforms. Characteristics of the PDs from the application of the high AC voltage up to the flashover of the insulator were then analyzed, and it was found that the features of the PDs in the near-flashover stage were significantly different to the previous stages.

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 140312-140318
Author(s):  
Feng-Chang Gu ◽  
Hong-Chan Chang ◽  
Yu-Min Hsueh ◽  
Cheng-Chien Kuo ◽  
Bo-Rui Chen

Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 937-945
Author(s):  
Ruihuan Zhang ◽  
Yu He ◽  
Yong Zhang ◽  
Shaohua An ◽  
Qingming Zhu ◽  
...  

AbstractUltracompact and low-power-consumption optical switches are desired for high-performance telecommunication networks and data centers. Here, we demonstrate an on-chip power-efficient 2 × 2 thermo-optic switch unit by using a suspended photonic crystal nanobeam structure. A submilliwatt switching power of 0.15 mW is obtained with a tuning efficiency of 7.71 nm/mW in a compact footprint of 60 μm × 16 μm. The bandwidth of the switch is properly designed for a four-level pulse amplitude modulation signal with a 124 Gb/s raw data rate. To the best of our knowledge, the proposed switch is the most power-efficient resonator-based thermo-optic switch unit with the highest tuning efficiency and data ever reported.


2013 ◽  
Vol 367 ◽  
pp. 541-543
Author(s):  
Yun Peng Li

This article focuses on research and implementation of a kind of solid storage system that is based on NAND flash which can store the data with high speed and huge capacity. A design with quad 1.25Gsps ADC and flash storage array with 1TB is demonstrated in the paper. The design is applied widely in many fields such as radar, communication and speech recognition. The detail of hardware development is also introduced in the thesis. In addition, a method is discussed to approve the reading and writing bandwidth by parallel operations on multiple pieces of flash. By using the method, the data bandwidth is arrived 6GB/S.


2012 ◽  
Vol 229-231 ◽  
pp. 1543-1546
Author(s):  
Xiao Bo Zhou ◽  
Min Xia ◽  
Hai Long Cheng

To improve data transmission performance of the data acquisition card, a design of high-speed data transmission system is proposed in the thesis. Using FPGA of programmable logic devices, adopting Verilog HDL of hardware description language, the design of modularization and DMA transmission method is implemented in FPGA. Eventually the design implements the data transmission with high-speed through PCI Express interface. Through simulation and verification based on hardware system, this design is proved to be feasible and can satisfy the performance requirements of data transmission in the high-speed data acquisition card applied in high-speed railway communication. The design also has some value of application and reference for a universal data acquisition card.


2014 ◽  
Vol 7 (6) ◽  
pp. 1693-1700 ◽  
Author(s):  
V. Fung ◽  
J. L. Bosch ◽  
S. W. Roberts ◽  
J. Kleissl

Abstract. Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system is presented that measures cloud shadow motion vectors to estimate power plant ramp rates and provide short-term solar irradiance forecasts. The cloud shadow speed sensor (CSS) is constructed using an array of luminance sensors and a high-speed data acquisition system to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud shadow motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground-measured irradiance (linear cloud edge, LCE), and a UC San Diego sky imager (USI). The CSS detected artificial shadow directions and speeds to within 15° and 6% accuracy, respectively. The CSS detected (real) cloud shadow directions and speeds with average weighted root-mean-square difference of 22° and 1.9 m s−1 when compared to USI and 33° and 1.5 m s−1 when compared to LCE results.


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