Effects of Conductor Pre-tension on Seismic Performance of ConverterTransformer Bushing

Abstract

UHV converter transformer is a critical equipment in converter substation, and bushing is an essential component affecting the seismic performance of it. The refined finite element modeling in ABAQUS software and seismic dynamic analysis was carried out on a ±800kV converter transformer bushing system to evaluate the bushing's seismic performance. The influence of the conductor's pre-tension on the dynamic performance and seismic response of bushing was studied. All parts of the model are simulated by the C3D4R solid elements. The simulation process shows that when the conductor's pre-tension is relatively small, the fundamental vibration mode is the vibration of the conductor it self. Increasing the pre-tension can effectively increase the natural vibration frequency. With the increase of pre-tension, the relative displacement of the valve-side conductor decreased by up to 31.9%, and the air-side conductor reached 31.6%. However, the stress in line-side bushing only increased by 5.9%. Based on the FE model analysis, the following conclusion can be drawn: 1) Appropriately increasing the pre-tension of the conductor can significantly reduce the relative displacement response between the conductor and the inner wall of the bushing. 2) Seismic displacement responses at the end of the valve side bushing are relatively large. It should be paid attention to in the engineering design to prevent traction damage or other problems affecting electrical functions.