Design Of35kV/4kA Cold Dielectric High Temperature Superconducting DC Cable Conductor

With development of power generation with new energy sourses and direct current (DC) transmission with long diatance, DC transmission is an important method for electricity power transmission. In the process of power transmission, how to reduce the loss has become a serious problem. The superconducting cable may effectively help reduce the power transmission losses due to its zero resistance at DC operation.Therefore, the research and developmentof DC High Temperature Superconducting (HTS) cable are of pracrical important.This thesis describes design of main insulation and conductor of35kV/4kA cold dieletric DC HTS power cable according to the development status of the DC superconducting power cable. Winding and electromagnetic parameters which are significant in design of the conductor of DC superconducting cable, as well as the design principles are proposed and analyzed. A software for design of DC superconducting cable design is obtained and used in several kinds of design principles; thus, a design example of35kV/4kA HTS power cable is given. For design of the main insulation of DC superconducting cable, the insulation characteristics of kraft paper and PPLP are experimentally measured at low temperature (77K). And these parameters obtained are used in the insulation design of the DC superconductivity power cable at35kV voltage grade. In addition, after a superconducting cable model is designed and fabricated, the experiment on the critical current and AC losses of the cable model with different frequencies and ripples are performed in liquid nitrogen. The experimental results show that the magnetic field at power supply terminals of superconducting cable can result in reducing critical current,and the AC loss of the superconducting cable conductor increases with increasing AC current ripple of DC transport current.