The equipment selection and layout of the 1 000 kV outgoing line high-reactance circuit is one of the key and difficult points in the design of 1 000 kV UHV substations.Taking Ganzi 1 000 kV Substation as an example

this paper elaborates the equipment selection process and design scheme for the 1 000 kV outgoing line high-reactance circuit in regions with high altitude and high seismic intensity.On the basis of the design experience of 1 000 kV high-reactance circuits in plain areas

combined with the specific condition parameters of high-altitude and high-seismic-intensity regions as well as the status of equipment research and development

this paper conducts a comparative analysis on the feasibility of three schemes:the scheme with both voltage transformers and surge arresters integrated into GIS equipment

the scheme with only a single type of equipment integrated into GIS equipment

and the fully open-type equipment scheme.Through technical and economic comparison

the fully open layout scheme is recommended.The scheme has been implemented and put into operation in Ganzi 1 000 kV Substation with normal operation performance.As the first UHV substation in China located in a high-altitude and high-seismic-intensity area

the equipment selection and layout of the outgoing line high-reactance circuit of Ganzi Substation are of important guiding significance for subsequent engineering projects.