scholarly journals Electrochromism of Viologen/Polymer Composite: From Gel to Insulating Bulk for High-Voltage Applications

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5901
Author(s):  
Yongjie Nie ◽  
Meng Zhang ◽  
Yuanwei Zhu ◽  
Yu Jing ◽  
Wenli Shi ◽  
...  
Keyword(s):  
Power Systems ◽  
Space Charge ◽  
Electric Fields ◽  
High Voltage ◽  
Vinylidene Fluoride ◽  
Power Equipment ◽  
Charge Accumulation ◽  
Charge Detection ◽  
Continuous Current ◽  
High Electric Fields

Power equipment operates under high voltages, inducing space charge accumulation on the surface of key insulating structures, which increases the risk of discharge/breakdown and the possibility of maintenance workers experiencing electric shock accidents. Hence, a visualized non-equipment space charge detection method is of great demand in the power industry. Typical electrochromic phenomenon is based on redox of the material, triggered by a voltage smaller than 5 V with a continuous current in μA~mA level, which is not applicable to high electric fields above 106 V/m with pA~nA operation current in power equipment. Until now, no naked-eye observation technique has been realized for space charge detection to ensure the operation of power systems as well as the safety of maintenance workers. In this work, a viologen/poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF–HFP)) composite is investigated from gel to insulating bulk configurations to achieve high-voltage electrical-insulating electrochromism. The results show that viologen/P(VDF–HFP) composite bulk can withstand high electric fields at the 107 V/m level, and its electrochromism is triggered by space charges. This electrochromism phenomenon can be visually extended by increasing viologen content towards 5 wt.% and shows a positive response to voltage amplitude and application duration. As viologen/P(VDF–HFP) composite bulk exhibits a typical electrical insulating performance, it could be attached to the surface of insulating structures or clamped between metal and insulating materials as a space charge accumulation indicator in high-voltage power equipment.

Novel Polar-fluoropolymer Blends with Tailored Nanostructures for High Energy Density and Low Loss Capacitor Applications

2012 ◽  
Vol 1403 ◽  
Author(s):  
Shan Wu ◽  
Minren Lin ◽  
David S-G. Lu ◽  
Lei Zhu ◽  
Q. M. Zhang
Keyword(s):  
Dielectric Loss ◽  
Energy Density ◽  
Electric Fields ◽  
Vinylidene Fluoride ◽  
High Energy ◽  
High Energy Density ◽  
Low Loss ◽  
Blend Films ◽  
Low Dielectric ◽  
High Electric Fields

ABSTRACTDielectric polymers with high energy density with low loss at high electric fields are highly desired for many energy storage and regulation applications. A polar-fluoropolymer blend consisting of a high energy density polar-fluoropolymer of poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) with a low dielectric loss polymer of poly(ethylene-chlorotrifluoroethylene) (ECTFE) was developed and investigated. We show that the two polymers are partially miscible which leads to blends with high energy density and low loss. Moreover, by introducing crosslinking to further tailor the nano-structures of the blends a markedly reduction of losses in the blend films at high field can be achieved. The crosslinked blend films show a dielectric constant of 7 with a dielectric loss of 1% at low field. Furthermore, the blends maintain a high energy density and low loss (∼3%) at high electric fields (> 250 MV/m).

OBIC Analysis of Different Edge Terminations of Planar 1.6 kV 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 1007-1010 ◽  
Author(s):  
Christophe Raynaud ◽  
Daniel Loup ◽  
Phillippe Godignon ◽  
Raul Perez Rodriguez ◽  
Dominique Tournier ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Semiconductor Devices ◽  
Optical Beam ◽  
Induced Current ◽  
Bipolar Diodes ◽  
High Electric Fields ◽  
Optical Beam Induced Current

High voltage SiC semiconductor devices have been successfully fabricated and some of them are commercially available [1]. To achieve experimental breakdown voltage values as close as possible to the theoretical value, i.e. value of the theoretical semi-infinite diode, it is necessary to protect the periphery of the devices against premature breakdown due to locally high electric fields. Mesa structures and junction termination extension (JTE) as well as guard rings, and combinations of these techniques, have been successfully employed. Each of them has particular drawbacks. Especially, JTE are difficult to optimize in terms of impurity dose to implant, as well as in terms of geometric dimensions. This paper is a study of the spreading of the electric field at the edge of bipolar diodes protected by JTE and field rings, by optical beam induced current.

scholarly journals Space Charge Accumulation Phenomena in PI under Various Practicable Environment

2021 ◽  
Author(s):  
Hiroaki Miyake ◽  
Yasuhiro Tanaka
Keyword(s):  
High Temperature ◽  
Space Charge ◽  
High Humidity ◽  
Power Equipment ◽  
Charge Accumulation ◽  
Insulation Materials ◽  
Breakdown Phenomenon ◽  
Operation Environment ◽  
Dielectric Insulation

Polyimide is widely used insulation materials, such as power equipment, motor windings, multi layer insulated, and so on. As the operation environment is high temperature, high humidity, radiation, the dielectric insulation characteristic is decreased compared with pristine one. Especially, the space charge characteristics are obtained big different. Furthermore, the breakdown phenomenon is frequently produced. In this chapter, we discuss the dielectric phenomena through the viewpoints of charge accumulation under the following environment. High temperature, High humidity, DC application, PWM application, Radio-active rays (electron, proton).

scholarly journals Polyethylene/Graphene Nanoplatelet Nanocomposite-Based Insulating Materials for Effective Reduction of Space Charge Accumulation in High-Voltage Direct-Current Cables

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Ji Sun Park ◽  
Young Sun Kim ◽  
Hyun-Jung Jung ◽  
Daseul Park ◽  
Jee Young Yoo ◽  
...  
Keyword(s):  
Space Charge ◽  
Electric Fields ◽  
Healing Process ◽  
Field Enhancement ◽  
Hydrophobic Surface ◽  
Threshold Concentration ◽  
Charge Accumulation ◽  
Organic Modifiers ◽  
Defect Healing ◽  
Optical Absorption Measurement

We have demonstrated a straightforward hydrophobic surface modification of graphene nanoplatelets (GNPs) through a defect-healing process to fabricate well-dispersed insulating low-density polyethylene (LDPE)/GNP nanocomposites and have confirmed their effective suppression of space charge accumulation. Without any organic modifiers, GNPs containing oxygen-based functional groups at the edges were successfully reduced at optimal high-temperature defect-healing condition and modified to have hydrophobic surface properties similar to those of the LDPE matrix. The degree of dispersion and the reproducibility of the mechanically melt-mixed LDPE/GNP nanocomposites were immediately analyzed by thickness-normalized optical absorption measurement. In the LDPE matrix, below the percolation threshold concentration, well-dispersed GNP fillers effectively acted as trapping sites under high electric fields, resulting in the successful suppression of packet-like space charge accumulation (field enhancement factor=1.04 @ 0.1 wt% LDPE/GNP nanocomposite).

scholarly journals Reducing leakage current and dielectric losses of electroactive polymers through electro-annealing for high-voltage actuation

RSC Advances ◽  
2019 ◽  
Vol 9 (23) ◽  
pp. 12823-12835 ◽  
Author(s):  
Francesco Pedroli ◽  
Alessio Marrani ◽  
Minh-Quyen Le ◽  
Olivier Sanseau ◽  
Pierre-Jean Cottinet ◽  
...  
Keyword(s):  
Leakage Current ◽  
Electric Fields ◽  
High Voltage ◽  
Electroactive Polymers ◽  
Dielectric Losses ◽  
High Electric Fields ◽  
Very High

The electro-annealed polymer, the E-TH sample, shows a reduction in leakage current of 80% for very high electric fields.

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