Dong Li’s research while affiliated with State Grid Electric Power Research Institute and other places

... These include the interfacial region between the polymer matrix and the particle, the particle aggregates, and the micro-and nanovoids. [13][14][15][16][17] Additionally, a very small amount of space charge is deeply trapped on the inner polar groups of the polymer insulator. The space charge at the defects induces the weak electric field distortion, so that these points could also act as starting points of electrical breakdown at a high voltage. ...

Reference:

Space charge behaviors and electrical insulation characteristics in EPDM/micro‐SiC composite with surface‐modified nano‐SiC for HVDC insulation

... HVDC power cable technology is critical to support the attainment of new-energy power transmission [2]. Since 2013, the voltage level of China's HVDC cross-linked polyethylene (XLPE) insulated cables has increased from ±160 kV to ±535 kV [3]. Current research attention has been paid to developing ±800 kV HVDC XLPE insulated power cables. ...

Reference:

Thermal Aging Properties of 500 kV AC and DC XLPE Cable Insulation Materials

... 7,8 In HVDC transmission systems, the cable, which has a multilayered insulation structure, is one of the most important parts to be managed safely because it has the highest risk of breakage in the system parts. [9][10][11][12][13][14] The cable's structure is composed of six parts: (1) a conductor, (2) a semiconductive conductor shield, (3) a cross-linked polyethylene (XLPE) insulating layer, (4) an insulation interface, (5) an ethylene-propylene-diene monomer (EPDM) insulating layer, and (6) an insulating shield. When HVDC flows through the conductor, almost all space charge is concentrated in the interfacial region between the conductive part and the polymer insulator or between the polymers, and a small amount of space charge is distributed in the bulk of the polymer insulation material. ...

Reference:

Space charge behaviors and electrical insulation characteristics in EPDM/micro‐SiC composite with surface‐modified nano‐SiC for HVDC insulation

... With the development of global energy interconnection, offshore wind power, crossing-sea and intercontinental connection projects are constructing progressively. HVDC and EHVDC Flexible cables have been widely used to meet the need of long-distance and large-capability electricity transmission [1]. However, space charges accumulating in XLPE insulation of HVDC cables will bring a local electric field distortion which may cause insulation breakdown [2]. ...

Reference:

Research on Difference between HVDC and HVAC Cable Shielding Materials

... The occurring of fast charge pulses at design values of applied electric field can lead to the aging of the insulation material also if no overvoltage transient happens during the cable lifetime. In order to observe this phenomenon with a sufficient spatial resolution, a small width of voltage pulses (<10 ns) is required to carry out the PEA measurements [41]. ...

Reference:

Review of the PEA Method for Space Charge Measurements on HVDC Cables and Mini-Cables