The effect of electrode material and semicon bonding on space charge dynamics of XLPE

Abstract

-This study sets out to explore the space charge characteristics of high voltage direct current (HVDC) cable grade crosslinked polyethylene (XLPE) using different electrode materials and configurations, ranging from sputtered gold to thermally bonded semi-conducting materials. The existence of both homo and hetero charges in HVDC cables is well known; however, the role of semi-conducting materials and the formation of space charge is critical and required more attention. Space charge accumulation at high electric stress was monitored using the pulsed electroacoustic (PEA) technique. Experimental results have shown that charge injection processes take place in all cases and the amount of charge and polarity of the dominated injected charge has significant dependence on the electrode material under the same applied electric field.

Investigation on effect of semiconducting screen on space charge behaviour of polypropylene‐based polymers for HVDC cables

“…In this section, space charge profiles of PP-based insulating polymers bonded with the prepared semiconducting materials will be investigated. Space charge distribution in insulation materials is sensitive and can be affected by many factors, including semiconducting materials, applied field, temperature, as well as interfacial interaction between the semiconducting layer and the insulating layer [11,36]. All voltage-on charge distribution profiles shown in the main context are normalised ones to exclude the interference of capacitive charges near the SC/PP interface (referred to section 2.3).…”

“…According to the experiments and simulation results in Wang et al and Xiao et al's work, local electric fields at semiconducting screen/insulation interface reduced with decreasing particle size of carbon black [20,21]. Hao et al demonstrated different bonding methods used for attaching semiconducting screen and insulation also made a difference [11]. Enhanced charge injection from the electrode was found at the interface of tightly bonded semiconducting screen/insulation films compared with conventional sputtered metal electrode/insulation and non-bonded semiconducting screen/insulation films.…”

“…It is widely believed that uniform dispersion of carbon black with high purity and small particle size leads to high electrical conductivity, less space charge accumulation in the insulation interface, and durable mechanical properties. As the developed semiconducting screen is attached to the insulation in practical applications, their compatibility and the interfacial effect should be attentively evaluated as well [8, 11, 20]. According to the experiments and simulation results in Wang et al.…”

“…Hao et al. demonstrated different bonding methods used for attaching semiconducting screen and insulation also made a difference [11]. Enhanced charge injection from the electrode was found at the interface of tightly bonded semiconducting screen/insulation films compared with conventional sputtered metal electrode/insulation and non‐bonded semiconducting screen/insulation films.…”

“…Extruded polymeric cable with coaxial structure is composed of metal conductor, conductor screen (inner semiconducting screen), insulation, insulation screen (outer semiconducting screen), metal sheath, and jacket from inner to outer layer [1]. Although the performance and voltage rating of the HVDC cable mainly relies on the properties of insulation, the critical role played by the semiconducting screen in improving the interfacial compatibility between the metal conductor and polymer insulation as well as suppressing charge injection for ensuring safety operation and long-term service of cables shall not be overlooked [8][9][10][11][12].…”