Research on Radiated Disturbance to Secondary Cable Caused by Disconnector Switching Operation

With the development of smart grids, the application of localized relay protection devices has greatly reduced the distance between the secondary equipment and the primary equipment. The secondary equipment will be in a more complex electromagnetic environment during the operation of the GIS disconnector. The present study takes the multi-path electromagnetic disturbance on the secondary cable caused by the disconnector switching operation of the domestic 1000 kV ultra-high voltage GIS test circuit as the research background, solves the field-line coupling problem based on the finite integral technique, and combines the multi-conductor transmission line theory to solve the radiation disturbance and obtains its influencing factors. The results demonstrate that the radiated disturbance accounted for 16% of the overall electromagnetic disturbance when both ends of the shielding layer are grounded. The use of grounding at both ends of the shielding layer, reducing the height of the secondary cable wiring, avoiding the parallel arrangement of the secondary cables and the GIS pipe mother, and installing a low-pass filter, have different levels of suppression effects on electromagnetic disturbances. The research results will guide the reasonable arrangement of secondary cables in GIS substations to some extent and have reference significance for the protection of secondary equipment.