Experimental And Simulation On110kV Cold Dielectric High Temperature Superconducting Cable

ABSTRACT:Engineering applications of high-temperature superconducting (HTS) cable needs to solve many problems. The key technical problems are the AC loss of HTS cable and as well as its access to the power system. The superiority and economy of HTS cable will be fully reflected only when the AC loss is low enough. The HTS cable access power system is also facing many problems. It may affect the reliability of power supply once a fault occurred in the transmission system, and even endanger the security of the HTS cable and the stability of power system. Therefore, the research of AC loss measurement technology and HTS cable operation in power system are related to safety of superconducting power transmission system, cost and application prospect of the HTS cable using in the power transmission system.In this thesis, the mathematical models of HTS tape and cable were established based on the characteristics of structure and E-J of YBCO tape. The electric parameters calculation method of HTS cable were established with full consideration the heat conduction process between different layers of cable and cooling medium. Magnetic field change law of HTS tape under the self-field and external magnetic field, and the calculation method of AC loss have been analyzed and obtained on the basis of the mechanism and properties when ac loss were generated in superconducting materials. The calculation theory and methods of AC loss were established considering the special structure of YBCO coating HTS cable.In order to study the AC loss variation of CD HTS cable, a novel AC loss measurement system for HTS cable is developed based on Lab VIEW and National Instruments (NI). AC losses of a0.2m,11OkV/1.5kA prototype HTS cable are measured at49.9Hz and60Hz frequency. Obtained results show that AC losses linearly increase with the transport current in logarithmic coordinates. The comparison results applying with compensation coil and theoretical calculation prove that the measurement system is feasibility and accuracy. In this thesis, AC loss of a model cable has been measured using the AC loss measurement system based on the method of calorimetry. The measurement results using the measurement system of calorimetry consistent with the theoretical calculation results basically. However, the measurement result using the calorimetry is slightly larger than the theoretical value compared to using the electrical measuring method. In the fifth chapter of this thesis, a simulation model of an110kV/3kA cold dielectric HTS cable is built using PSCAD/EMTDC based on the critical characteristics of the HTS cable considering the quench effects which is calculated by using MATLAB. An external short-circuit fault is simulated in a110kV HTS transmission line and the power flow distributions with HTS cable and without HTS cable are compared. The comparison results show that the HTS cable has greater short-circuit capacity and is beneficial to the power grid voltage stability and regulation. Finally, an experiment platform with the25kA@ls impact current is also built with HTS prototype cables. An impact experiment with the HTS prototype cables has been completed under the2times rated current of the cable. The variation in the HTS cable has been obtained with the impact current.