Generation and Dissipation of Negative Heterocharges in XLPE and EPR

Sekii, Y.; Maéno, Takashi

doi:10.1109/tdei.2009.5128504

Cited by 31 publications

(21 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Decrease of charge density over time : (a) decrease of charge density (b) percentile decrease of charge density…”

Section: Generation Of Charges In Cross‐linked Polyethylenementioning

confidence: 99%

See 1 more Smart Citation

Charge generation and electrical degradation of cross‐linked polyethylene

Sekii¹

2018

IEEJ Transactions Elec Engng

Self Cite

View full text Add to dashboard Cite

Cross‐linked polyethylene is a chemically stable polymeric dielectric material with high dielectric strength, low dielectric constant and a small dissipation factor. Because of these excellent dielectric properties, cross‐linked polyethylene is used as an insulating material for electric power cables. Based on the results of much research working as an engineer of a cable manufacturer and in academia, this article describes the outline of charge generation under DC voltage stress and electrical degradation occurring in the material under AC voltage stress. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

show abstract

“…Decrease of charge density over time : (a) decrease of charge density (b) percentile decrease of charge density…”

Section: Generation Of Charges In Cross‐linked Polyethylenementioning

confidence: 99%

“…During work as an engineer of a cable manufacturer, and in academia, using this dielectric material, the author has conducted many studies. Based on those studies, the generation of electrical charges created in the material and the material degradation is described here [1][2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Charge generation and electrical degradation of cross‐linked polyethylene

Sekii¹

2018

IEEJ Transactions Elec Engng

Self Cite

View full text Add to dashboard Cite

show abstract

“…It has been reported that heterocharges are formed if cable insulation contains sulfur-based antioxidants. (17) Moreover, it is considered that excited electrons from impurities such as the residue of cross-linking agents are involved in the generation of electron-hole pairs in the bulk. (17) It was reported that the electrical conduction of an amorphous polymer such as EPR is higher than that of a semicrystalline polymer such as XLPE because of the formation of localized energy levels.…”

Section: Heterocharge Accumulation In the Bulk And Positive Homochargmentioning

confidence: 99%

“…(17) Moreover, it is considered that excited electrons from impurities such as the residue of cross-linking agents are involved in the generation of electron-hole pairs in the bulk. (17) It was reported that the electrical conduction of an amorphous polymer such as EPR is higher than that of a semicrystalline polymer such as XLPE because of the formation of localized energy levels. (18) Therefore, it is important to consider energy levels to understand the space charge behavior.…”

Section: Heterocharge Accumulation In the Bulk And Positive Homochargmentioning

confidence: 99%

Space Charge Behavior under Thermal Gradient in Cross-linked Polyethylene and Ethylene-Propylene Rubber

2017

Sensors and Materials

View full text Add to dashboard Cite

The direct observation of space charge injection, transport, accumulation, and recombination in solid dielectrics, as well as their spatial evolution over time, is of considerable importance in the investigation of design stress and the aging mechanism of engineering dielectrics under a high electric field. In a high-voltage direct current (HVDC) power cable with an expected temperature gradient at operating temperature and electric field, the spatial variation of the ratio of two electromagnetic constitutive parameters of the cable dielectric, the permittivity vs conductivity, acquires the presence of space charge across the insulation. Such a space charge distribution depends strongly on the temperature and electric field coefficients of these electromagnetic constitutive parameters. In addition, the injection of charges across the conductor/ insulation interface and the subsequent transport, trapping and detrapping of these charges over various chemical and physical defects further enhance the electric field distortion and aging of cable dielectrics. Numerous studies have been conducted under a parallel-plate configuration to understand such a space charge effect. However, nearly all of them were conducted under uniform isothermal conditions. The ability to perform a space charge profiling study under a thermal gradient in the development phase of new extruded high-voltage direct current cable materials brings in the most value upstream. In this study, through model-aided design, a parallel-plate, pulsed-electroacoustic (PEA) space charge profiling technique is extended to include a thermal gradient in flat dielectric samples. The space charge behavior and dynamics within flat dielectric specimens in the presence of a thermal gradient have been studied extensively through a modified PEA system to provide insights into the high-field aging mechanisms of new materials developed for energy-efficient power devices and renewable integration.

show abstract

“…One study shows a decrease of space charge density at high field for high moisture content in XLPE whereas the space charge accumulation increased at lower moisture content [18]. The generation of negative heterocharge in XLPE with varying relative humidity has been investigated in [19,20] where it was found that absorbed moisture and charge density exhibit a linear relationship.…”

Section: B High Voltage DCmentioning

confidence: 99%

Material considerations for submarine high voltage XLPE cables for dynamic applications

Sonerud

Eggertsen

Nilsson

et al. 2012

2012 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

View full text Add to dashboard Cite

Special consideration is necessary choosing materials and selecting design for dynamic cables due to the mechanical stress, sometimes in combination with a wet design, experienced by the cable. For high voltage cables (>36 kV) this is mainly related to the required (IEC 60840) metallic water barrier and for wet solutions the influence of water treeing and the associated accelerated electrical aging is of concern. Lead is commonly used as a radial water barrier for high voltage cables but the fatigue resistance is inferior to steel and most other metallic materials due to its low melting temperature and poor mechanical properties. For these reasons it is generally not considered suitable as a radial water barrier for dynamic power cables. Alternatives such as longitudinally welded copper sheaths have proved to be viable alternatives to lead and studies on nonmetallic barriers have been performed which show promising results. For wet medium voltage designs or designs which allow some moisture ingress into the insulating material water treeing is often a concern. However, it has been shown that high relative humidity (>70%) is necessary for water tree inception. By delaying the water ingress with sheaths and swelling tapes the time to reach critical humidity levels in the material can be increased from 1 month to several decades. The influence of hydrostatic pressure and compressive stress has been found to diminish water tree growth whereas tensile stress enhances it. For dc voltages there are indications that both humidity and mechanical stress can increase accumulation of charge in the insulating material. It has also been shown that moisture ingress will increase the conductivity which could influence breakdown strength negatively.

show abstract

Generation and Dissipation of Negative Heterocharges in XLPE and EPR

Cited by 31 publications

References 10 publications

Charge generation and electrical degradation of cross‐linked polyethylene

Charge generation and electrical degradation of cross‐linked polyethylene

Space Charge Behavior under Thermal Gradient in Cross-linked Polyethylene and Ethylene-Propylene Rubber

Material considerations for submarine high voltage XLPE cables for dynamic applications

Contact Info

Product

Resources

About