Study on the nanoparticle-modification of working temperature and breakdown characteristics for insulating materials in DC cables

In order to improve the insulation performance of commercial DC cable materials, including raising their working temperature and enhancing their breakdown performance, we added MgO nanoparticles and Al(OH)₃ nanoparticles to commercial DC cable materials, respectively, and fabricated two kinds of nanocomposite specimens. Moreover, we tested the conductivity under different temperatures, space charge distribution under different temperatures (using the PEA method), and breakdown characteristics under different polarity of the specimens. The results show that adding either MgO or Al(OH)₃ nanoparticles to the DC cable materials will reduce the thermal influence on both conductivity and the space charge characteristics, increase the materials' electrical conductivity under high temperature, enhances their space charge properties under high temperature, and reduce the electric field distortion in DC cables made of the materials. In the meantime, adding Al(OH)₃ can obviously improve the materials' short-termbreak down performance by up to 25 percent, whereas adding MgO nanoparticles fails to get any similar improvement. Hence it is concluded that adding Al(OH)₃ nanoparticles is more effective in improving the performances of commercial DC cable materials in the aspects of increasing the working temperature and enhancing the breakdown performance.