Study On Layout Design Optimization Of Main Transformers And Reactive Switchgear Arrangement Of EHV Substations

Improving operation reliability and saving land occupation and project investment are main objectives of engineering design optimization. The area of main transformers and reactive switchgear arrangement of an EHV substation is mainly used for arranging the main transformers and the reactive power compensation devices which are connected to the low-voltage side of the main transformers. Along with the high-speed development of power grid construction, the scale and capacity of substation transformers are becoming increasingly larger and the number of reactive power compensation devices is constantly increasing, which leads to the increasingly prominent problems of large land occupation of main transformers and reactive switchgear arrangement.The systematic studies are, however, rarely conducted on optimization of the main transformer and its low-voltage side.This paper, based on the development and application of power grid primary equipment, the status quo of power grid engineering design and relevant codes, makes a systematic study on the voltage levels on the low-voltage side of main transformers, the electric main bus connection modes, and type selection and layout of switchgear, reactive compensation devices and reactive switchgear arrangement; and proposes new thinkings for design of low-voltage side of main transformer, which includes layout optimization of capacitors and reactors on the condition of keeping the equipment investment unchanged for reducing land occupation; active use of new technology and new equipment for saving land and improving operation reliability. According to the main features of present EHV substations, the paper also proposes the optimization principles and design schemes, which can provide an important reference for other project designs.Land is a kind of nonrenewable resources and therefore it is imperative to carry out optimization design of the low-voltage side of main transformers for reasonable use of land and protection of plough land. The study of this paper proposes good solutions for the above-said land saving problems and is very important for improving the integral design level of substations and improving the operation reliability.