Research On Space Charge Test And Analysis Techniques Of Plastic Insulated HVDC Cables

HVDC Cables will be used vastly in the future HVDC transmission system since they have a bundle of advantages such as higher working electric stress, thinner insulation, smaller diameter, lighter weight, good flexibility, lower dielectric loss and conductor loss, environmental friendliness and no AC magnetic field. However, Compared with AC power system, the research of HVDC power cables is hysteretic. One of the problems that should be conquered is space charge effect in the development of HVDC cables, especially plastic insulated HVDC cables. There are lots of local traps in the plastics. When they are used as the main insulation of HVDC cables, space charge effect becomes very severe. The presence of space charge could affect the dielectric strength and result in the distortion of electric field and none electric field. Therefore, the crucial problem of developing plastic insulated HVDC cable is to suppress the accumulation of space charge in insulating materials. As a result, the research on space charge test and analysis techniques of plastic insulated HVDC cables becomes particularly important.This project focused on the space charge test of plastic insulated HVDC cables. Basing on previous space charge research of insulating materials in pulsed electro-acoustic (PEA) method, we designed space charge test system for plastic insulated HVDC cables which is capable of acquiring, recovering space charge distribution signal and calculating electric field in the cable's insulation.In this thesis, principles of hardware design and algorithms of signal processing were analyzed. The hardware and software of space charge test system for the insulation development of plastic insulated HVDC cables were realized, which provide a solid experimental and analytic basis for researching the short-term and long-term space charge effects on HVDC cable insulation.