7 results
Search Results
2. Dielectric frequency response of oil-impregnated paper: The effect of partial discharges compared to other influences.
- Author
-
Niasar, M. Ghaffarian, Taylor, N., Edin, H., and Kiiza, R. Clemence
- Subjects
- *
DIELECTRICS , *FREQUENCY response , *PAPER , *PARTIAL discharges , *ELECTRODES , *ELECTRIC conductivity - Abstract
In this paper, the influence of partial discharges (PD) on the subsequent dielectric properties of oil-impregnated paper (OIP) is investigated. Dielectric frequency response (DFR) of OIP is investigated at varied levels of moisture, thermal aging, temperature, oil conductivity and electrode material, to allow comparison of these influences. It is shown that PD activity inside OIP can significantly change the real and imaginary parts of permittivity of the paper layers, especially in the frequency range below 100 Hz. It is shown that even if the PD activity is concentrated on a few percent of the test sample, the real part of permittivity measured on the entire sample after a few tens of hours of PD activity can increase up to 10 times at very low frequencies (∼ 1 mHz) and the imaginary part of the permittivity can increase up to 100 times at low frequencies (∼ 1 Hz). The change of the real and imaginary parts of permittivity due to PD activity is permanent. It is very similar to the change caused by thermal aging, and somewhat similar to the change caused by moisture and higher oil conductivity. It is also shown that the dissipation factor of OIP in contact with copper and brass increases, even in the absence of PD, but contact with aluminum and stainless steel has no influence on DFR of OIP. The results suggest that the influence of PD can be significant when estimating the moisture content or the level of thermal aging of OIP with DFR method. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
- View/download PDF
3. Partial discharge characteristics in oil-paper insulation under combined AC-DC voltage.
- Author
-
Sha, Yanchao, Zhou, Yuanxiang, Li, Jinzhong, and Wang, Jianyi
- Subjects
- *
PARTIAL discharges , *ELECTRIC insulators & insulation , *PAPER , *AC DC transformers , *ELECTRIC potential , *HEATING & ventilation industry , *ELECTRIC transformers - Abstract
Heretofore, unlike HVAC transformers, there is not much experience in both insulation design guides and test methods for ultra HV converter transformers. This special insulation phenomenon is very prominent due to the complication of voltage applied on valve-side windings of converter transformers. There is a severe lack of empirical research on partial discharge in oil-paper insulation under the combined ACDC voltage. The study in this paper provides a timely research into the issues. Nine possible configurations, which intent to simulate different defects in the transformer, have been investigated. The PD inception voltages varied ratios of combined AC-DC voltages were conducted. The discharge magnitude and its relation with the applied voltage for selected four common configurations were obtained during voltage increasing and decreasing respectively, which presented the PD initiating process and also reflected the insulation behavior of dielectrics. Besides, the Finite Element Analysis Soft was used to propose the effect of morphology of electrode surface (3 dimensional roughness is approximately 0.03 mm) on PD characteristics, which is very lacking in the previous references. The roles of DC and AC component in PD characteristics were discussed in the context of the relevant work in literatures. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
4. Inkjet Printable Flexible Thin-Film NCQD Photodetectors on Unmodified Transparency Films.
- Author
-
Jingda Wu and Lin, Lih Y.
- Abstract
We proposed and experimentally demonstrated a cost-efficient and easy-to-fabricate flexible thin-film nanocrystal quantum dot (NCQD) photodetector, by sandwiching a piece of NCQD-soaked tracing paper between two PEDOT:PSS electrodes. The highly conductive and transparent multilayer polymer electrodes are printed with an office inkjet printer without further patterning on commercial unmodified transparency films. The tracing paper is able to act as both the bed for NCQD attachment and the interspacing layer to prevent short-circuiting in vertical devices. Consistent increase in device performance is observed when the bending radius becomes smaller. Linear I-V characteristics are obtained, which show our device structure works as a photoconductor. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
5. Low-Voltage Oxide-Based TFTs Self-Assembled on Paper Substrates With Tunable Threshold Voltage.
- Author
-
Sun, Jia, Jiang, Jie, Lu, Aixia, Dou, Wei, Zhou, Bin, and Wan, Qing
- Subjects
- *
THIN film transistors , *THRESHOLD voltage , *LOW voltage systems , *ELECTRONIC modulation , *ELECTRODES , *PAPER - Abstract
Oxide-based thin-film transistors (TFTs) with a lateral in-plane electrode are self-assembled on paper substrates, and the electrical modulation effect of the in-plane electrode is investigated. A \SiO2-based solid-electrolyte film with high specific capacitance is used as the gate dielectric, and the operation voltage is reduced to less than 2.0 V. The threshold voltage (Vth) of such paper TFTs is tuned from -0.98 to 0.94 V by different voltage biases on the in-plane electrode. The threshold voltage shift (\Delta Vth) can be described by \Delta Vth = -(CG2/CG1)VG2, where CG2 and CG1 are the in-plane electrode and bottom-gate specific capacitance values. High electrical performance with a current on/off ratio of \6 \times \10^5 \sim \10^6, a subthreshold swing of 0.14 \sim 0.19 V/dec, and a mobility of \8.64 \sim \9.45\ \cm^2/\V\cdot \s is obtained at different in-plane electrode voltage biases. Such low-voltage paper TFTs are promising for low-cost and portable electronics. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
6. A Foldable Microplasma-Generation Device on a Paper Substrate.
- Author
-
Hsu, Cheng-Che, Tsai, Jheng-Han, Yang, Yao-Jhen, Liao, Ying-Chih, and Lu, Yen-Wen
- Subjects
- *
PLASMA gases , *ELECTRODES , *HELIUM plasmas , *DIRECT currents , *SOLUTION (Chemistry) , *DROPLETS , *ELECTRIC discharges - Abstract
We report the fabrication of a plasma-generating device on a paper substrate. This device was fabricated using a screen print process. Plasmas were ignited between two parallel electrodes with a plasma gap of 237 to 710 \mu\m using a dc power source. We demonstrated that a stable helium plasma can be sustained when the substrate is flat, rolled, and folded along various orientations. When the plasma was ignited with a 0.2-\mu\L salt solution droplet with 1.4, 4.6, and 7.8 ng of Li, Na, and K respectively applied to the discharge gap, clear metallic emission lines emanated from the plasma. Our result demonstrates that this paper-based plasma device can be used in analytical applications.\hfill[2012-0006] [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
7. Origami microfluidic paper-analytical-devices (omPAD) for sensing and diagnostics
- Author
-
Yu Chen, Meera Punjiya, Sameer Sonkusale, and Chung Hee Moon
- Subjects
Paper ,Engineering ,Optical Phenomena ,Dopamine ,Point-of-Care Systems ,Microfluidics ,Biosensing Techniques ,02 engineering and technology ,Integrated circuit ,01 natural sciences ,law.invention ,Imaging, Three-Dimensional ,Sensor array ,law ,Cleanroom ,Electronic engineering ,Microtechnology ,Electronics ,Electrodes ,business.industry ,010401 analytical chemistry ,Oxides ,Electrochemical Techniques ,Microfluidic Analytical Techniques ,021001 nanoscience & nanotechnology ,Potentiostat ,0104 chemical sciences ,Semiconductors ,CMOS ,Metals ,0210 nano-technology ,business - Abstract
Recent research activities in the area of low-cost sensing and diagnostics that are realized on cellulosic paper substrate are presented. First a three-dimensional origami paper-based analytical device (omPAD) with multiple electrochemical sensors, an integrated sample reservoir and tight integration with a custom CMOS potentiostat is presented. Second, an optical sensor array with built-in microfluidic channel for sample delivery is presented. The sensors are fabricated using a combination of wax printing and screen-printing using a solution based approach in ambient conditions without the need for expensive fabrication equipment or a cleanroom. Readout is based on using existing consumer grade electronic devices like flatbed scanner (for optical sensor) or custom designed CMOS potentiostat (for electrochemical sensors). Together the 3D paper-based analytical device with integrated sensor, microfluidics and portable readout instrumentation demonstrates a low-cost, self-contained system suitable for sensing and point-of-care diagnostics.
- Published
- 2016
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.