Research On The Disturbance Of The Secondary Cable Due To UHV GIS Disconnect Switch Operations

When disconnect switcher is operating in UHV GIS substation; it will result in electric arc breakdown and reigniting between switchgear contacts. Hence, produce very fast transient over-voltage (VFTO). VFTO is characterized by high peak value, short rise time and wide frequency range. The transient electromagnetic field that generated by VFTO would coupling on the secondary cable through space or conducting.MTL, FDTD and MOM method are mainly used while domestic and foreign scholars are researching on VFTO coupling to the secondary cable. The thesis firstly researched the wide frequency electrical parameters of the cable which is common seen in substations. Then, these parameters coupled with MTL method and field-to-line method were used to establish the model which described the process caused by VFTO coupling to the cable through two or more shielding layers. According to the simulation results, disturbance voltage on the secondary cable was obtained and analyzed in the time domain and frequency domain. Finally, a dedicated measurement system suit for strong electromagnetic environment which could be used to measure the induced voltage on secondary cable caused by VFTO on the UHV GIS apparatus and in the UHV GIS substation was developed. The measurement results were also analyzed in the time domain and frequency domain.The measurements and simulation results could provide a quantitative basis for the research on the secondary system in UHV GIS substation.