scholarly journals Electrical Characterization of a New Crosslinked Copolymer Blend for DC Cable Insulation

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1434 ◽  
Author(s):  
Sarath Kumara ◽  
Xiangdong Xu ◽  
Thomas Hammarström ◽  
Yingwei Ouyang ◽  
Amir Masoud Pourrahimi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electric Field ◽  
Surface Potential ◽  
High Voltage ◽  
Direct Current ◽  
Electrical Characterization ◽  
Copolymer Blend ◽  
New Material ◽  
Potential Decay

To design reliable high voltage cables, clean materials with superior insulating properties capable of operating at high electric field levels at elevated temperatures are required. This study aims at the electrical characterization of a byproduct-free crosslinked copolymer blend, which is seen as a promising alternative to conventional peroxide crosslinked polyethylene currently used for high voltage direct current cable insulation. The characterization entails direct current (DC) conductivity, dielectric response and surface potential decay measurements at different temperatures and electric field levels. In order to quantify the insulating performance of the new material, the electrical properties of the copolymer blend are compared with those of two reference materials; i.e., low-density polyethylene (LDPE) and peroxide crosslinked polyethylene (XLPE). It is found that, for electric fields of 10–50 kV/mm and temperatures varying from 30 °C to 70 °C, the DC conductivity of the copolymer blend is in the range of 10−17–10−13 S/m, which is close to the conductivity of crosslinked polyethylene. Furthermore, the loss tangent of the copolymer blend is about three to four times lower than that of crosslinked polyethylene and its magnitude is on the level of 0.01 at 50 °C and 0.12 at 70 °C (measured at 0.1 mHz and 6.66 kV/mm). The apparent conductivity and trap density distributions deduced from surface potential decay measurements also confirmed that the new material has electrical properties at least as good as currently used insulation materials based on XLPE (not byproduct-free). Thus, the proposed byproduct-free crosslinked copolymer blend has a high potential as a prospective insulation medium for extruded high voltage DC cables.

Electrical Characterization of the Graphene-SiC Heterojunction

2012 ◽  
Vol 717-720 ◽  
pp. 641-644
Author(s):  
Travis J. Anderson ◽  
Karl D. Hobart ◽  
Luke O. Nyakiti ◽  
Virginia D. Wheeler ◽  
Rachael L. Myers-Ward ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Charge Carrier ◽  
Graphene Sheet ◽  
Carrier Transport ◽  
Electrical Characterization ◽  
Epitaxial Graphene ◽  
Charge Carrier Transport ◽  
Semiconductor System ◽  
Significant Research

Graphene, a 2D material, has motivated significant research in the study of its in-plane charge carrier transport in order to understand and exploit its unique physical and electrical properties. The vertical graphene-semiconductor system, however, also presents opportunities for unique devices, yet there have been few attempts to understand the properties of carrier transport through the graphene sheet into an underlying substrate. In this work, we investigate the epitaxial graphene/4H-SiC system, studying both p and n-type SiC substrates with varying doping levels in order to better understand this vertical heterojunction.

Three-Dimensional Potential and Electric Field Distributions in HV Cable Insulation Containing Multiple Cavities

2013 ◽  
Vol 845 ◽  
pp. 372-377 ◽  
Author(s):  
Nabipour Afrouzi Hadi ◽  
Zulkurnain Abdul-Malek ◽  
Saeed Vahabi Mashak ◽  
A.R. Naderipour
Keyword(s):  
Electrical Properties ◽  
Electric Field ◽  
High Voltage ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Low Dielectric ◽  
Underground Cable ◽  
Insulation Failure ◽  
Field Distributions ◽  
Hv Cable

Cross-linked polyethylene is widely used as electrical insulation because of its excellent electrical properties such as low dielectric constant, low dielectric loss and also due to its excellent chemical resistance and mechanical flexibility. Nevertheless, the most important reason for failure of high voltage equipment is due to its insulation failure. The electrical properties of an insulator are affected by the presence of cavities within the insulating material, in particular with regard to the electric field and potential distributions. In this paper, the electric field and potential distributions in high voltage cables containing single and multiple cavities are studied. Three different insulating media, namely PE, XLPE, and PVC was modeled. COMSOL software which utilises the finite element method (FEM) was used to carry out the simulation. An 11kV underground cable was modeled in 3D for better observation and analyses of the generated voltage and field distributions. The results show that the electric field is affected by the presence of cavities in the insulation. Furthermore, the field strength and uniformity are also affected by whether cavities are radially or axially aligned, as well as the type of the insulating solid. The effect of insulator type due the presence of cavities was seen most prevalent in PVC followed by PE and then XLPE.

Thermal breakdown in high voltage direct current cable insulations due to space charges

2018 ◽  
Vol 37 (5) ◽  
pp. 1689-1697 ◽  
Author(s):  
Christoph Jörgens ◽  
Markus Clemens
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Direct Current ◽  
Aging Effect ◽  
Radial Symmetry ◽  
Thermal Breakdown ◽  
Content Type ◽  
High Voltage Direct Current ◽  
Space Charges

Purpose In high voltage direct current (HVDC), power cables heat is generated inside the conductor and the insulation during operation. A higher amount of the generated heat in comparison to the dissipated one, results in a possible thermal breakdown. The accumulation of space charges inside the insulation results in an electric field that contributes to the geometric electric field, which comes from the applied voltage. The total electric field decreases in the vicinity of the conductor, while it increases near the sheath, causing a possible change of the breakdown voltage. Design/methodology/approach Here, the thermal breakdown is studied, also incorporating the presence of space charges. For a developed electro-thermal HVDC cable model, at different temperatures, the breakdown voltage is computed through numerical simulations. Findings The simulation results show a dependence of the breakdown voltage on the temperature at the location of the sheath. The results also show only limited influence of the space charges on the breakdown voltage. Research limitations/implications The study is restricted to one-dimensional problems, using radial symmetry of the cable, and does not include any aging or long-term effect of space charges. Such aging effect can locally increase the electric field, resulting in a reduced breakdown voltage. Originality/value A comparison of the breakdown voltage with and without space charges is novel. The chosen approach allows for the first time to assess the influence of space charges and field inversion on the thermal breakdown.

Electrical Characterization of E7 Liquid Crystal Molecules under the Impact of an External Electric Field (THz): A Theoretical approach

2020 ◽  
Vol 15 (2) ◽  
pp. 95-101
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Order Parameter ◽  
Optical Switching ◽  
Rapid Change ◽  
Electrical Characterization ◽  
Optical Switching Devices ◽  
The Impact ◽  
Orientation Of Molecules

In this work, different parameters of E7 liquid crystal (LC) have been calculated under the influence of an electric field in THz frequency. The E7 LC parameters have positive as well as negative values of order parameter and birefringence under the influence for an electric field. The director angle of E7 LC shows fast fluctuations above the angle θ=45° and due to rapid change in the orientation of molecules, fast electro-optical switching devices based on E7 LC can be designed. The refractive index of the E7 LC maintains stability in THz frequency.

Optical and Electrical Properties of Cd Te Laser-Synthetized

1982 ◽  
Vol 13 ◽  
Author(s):  
L. Baufay ◽  
A. Pigeolet ◽  
R. Andrew ◽  
L.D. Laude
Keyword(s):  
Electrical Properties ◽  
Single Crystal ◽  
Electrical Characterization ◽  
Point Of View ◽  
Optical And Electrical Properties ◽  
Impurity States ◽  
Absorption Measurements ◽  
Forbidden Gap

ABSTRACTOptical and electrical characterization of CdTe synthetized by laser irradiationofamultilayer film of alternately Cd and Te is achieved. Optical absorption measurements evidence the good quality of these films and show that they have behaviour comparable to the single crystal. The influence of the irradiation conditions on the electrical properties of such CdTe films is discussed; they are compared to single crystal from the point of view of resistivity. It is shown that it is possible to prepare by this means samples devoid of impurity states in the middle of the forbidden gap. Finally, the ohmicity of Au, Al, Cr, ITO and non irradiated Cd/Te sandwich contacts is tested.

Sign in / Sign up

Export Citation Format

Share Document