Research on the Engineering Application Feasibility of Combined Large Capacity Wall Bushing

The traditional UHVDC wall bushing is an Integral structure, and the insulation structure is made of epoxy capacitive core as main insulation and SF6 as auxiliary insulation, or pure gas structure with voltage equalizing electrode. Whatever the structure is, there are many problems such as difficult manufacture, inconvenient installation and poor seismic performance after capacity increase. In this paper, a kind of combined large capacity wall bushing structure is proposed, the new structure consists of indoor bushing, outdoor bushing and wall-through component. The wall-through component is installed on the ground, which can significantly improve the seismic performance and reduce the steel structure requirements of the valve hall. In the meantime, it has the advantages of convenient transportation and installation, high manufacture quality, simple maintenance, short delivery cycle, etc. Based on this, the production feasibility, technical economy and operation reliability of the new wall bushing are evaluated, and the key problems to be solved in the engineering application are studied, including the match of valve hall design, the selection of indoor/outdoor bushing external insulation, the connection of current carrying conductors for each part, the design and optimization of insulation structure, the performance index and test and assessment method of the combined wall bushing. The research results can guide the design and development of new wall bushing, which is of great significance to promote the technical progress and engineering application of it.