Surface Charge Characteristics of DC-GIL Insulator Under Multiphysics Coupled Field: Effects of Ambient Temperature, Load Current, and Gas Pressure

et al. 2022

iEnergy

The construction of the future energy structure of China under the 2050 carbon-neutral vision requires compact direct current (DC) gas-insulation equipment as important nodes and solutions to support electric power transmission and distribution of long-distance and large-capacity. This paper reviews China's 10-year progress in DC gas-insulated equipment. Important progresses in basic research and industry perspective are presented, with related scientific issues and technical bottlenecks being discussed. The progress in DC gas-insulated equipment worldwide (Europe, Japan, America) is also reported briefly.

Section: Charge Simulation and Calculationmentioning

confidence: 99%

mentioning

confidence: 99%

China's 10-year progress in DC gas-insulated equipment: From basic research to industry perspective

et al. 2022

iEnergy

“…By substituting (1) to ( 5) and ( 2) to ( 6), the ion transport equations of positive and negative ions are described in (7) and (8):…”

Section: Conduction Mechanismmentioning

confidence: 99%

“…Winter et al investigated the surface charge accumulation characteristics of a cylindrical insulator both at stationary [6] and transient [7] states in air condition via measurement and simulation. Compared with measurements, the application of simulation on the physical process of charge accumulation gains great advantages on the study of surface charge distribution with advanced computing technologies [8,9]. Recently, many researchers have focused on the simulation of surface charge accumulation characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effects of volume and surface conductivity on the surface charge and electric field characteristics of the tri‐post insulator in SF ₆ ‐filled ± 500 kV DC‐GIL

IET Generation Trans & Dist

Cao

et al. 2022

Self Cite

Herein, the surface charge characteristics of a tri‐post insulator in a ± 500 kV direct current gas‐insulated transmission lines (DC‐GIL) filled with SF6 are thoroughly studied. The influences of volume and surface conductivity of the insulator on the surface charge and consequent electric field distribution are discussed. An improved method is introduced to obtain the distribution of surface charge with considerable accuracy and efficiency for the calculation. It is found that with increasing the volume conductivity, the dominative conduction mechanism changes from surface conduction to bulk conduction, while the inverse variation appears with increasing the surface conductivity. During the variation of electric conductivity, obvious effect of surface charge accumulation is found on the electric field distribution involving the variation of peak electric field strength and its location. Besides, high charge density usually appears along with low peak field strength during this variation. It can be concluded that the surface charge accumulation should be paid special attention when analysing the insulation characteristics of tri‐post insulators. The variation of volume and surface electric conductivity should be thoroughly considered.

“…In fact, when DC GIL is put into service, the large current along the central high-voltage electrode will generate Joule heat, which enables the spacer surface to form a temperature gradient distribution [16]. The existence of thermal gradient on spacer surface will promote the migration of surface charge, then increase the amount of surface charges and ultimately decrease surface insulation strength [17,18]. However, the surface charge and electric field regulation under the thermal gradient field is less paid attention to, which still needs the systematic and deep investigation.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐dependent adaptive conductivity coating for surface charge release and electric field control under electro‐thermal coupling field

Xue

et al. 2023

High Voltage

Surface charge accumulation is the potential criminal for surface insulation failure on spacers under direct current (DC) voltages. The existence of thermal gradient posing the difficulty of surface charge regulation. This study proposes a temperature‐dependent adaptive conductivity coating technique for surppressing surface charge accumulation under electro‐thermal coupling field. A two‐dimensional axis‐symmetrical simulation model regrading surface charge computation is established. The effects of thermal gradients and coating conductivity on surface charge and electric field distribution are investigated. The results show that the thermal gradient increases the bulk conductive current, therefore aggravating surface charge accumulation. The effects of the coating condcutivity on surface charge and electric field contains three stages. The lower coating conductivity leads to aggravated homo‐polarity charge accumulation. By increasing the coating conductivity, the surface charge and electric field are significantly suppressed at the obtained optimal conductivity, where the bulk and surface conductive current reach a balance stage. Continuously increasing the coating conductivity results in aggravated hetero‐polarity charges. Besides, the increase of thermal gradient to an appropriate extent contributes to the further suppression of surface charge on coated spacers. It is hoped that this study could provide some references for designing highly reliable DC GIL under electro‐thermal coupling field.