| In recent years,the modular substation newly promoted and applied by State Grid Corporation of China is one of the achievements in the development of substation construction.It rearranges the overall functional requirements and equipment configuration of the station.Optimize equipment integration through design concept,maximize prefabrication,minimize installation,prefabricate auxiliary equipment,prefabricate buildings,prefabricate optical cables and other key technologies,standardize design and factory processing.It has many advantages such as high reliability and high construction efficiency.Based on the 110 k V airport substation construction project,this paper fully integrates the "modular" design concept into it.The main work includes:(1)This paper introduces the load development and network characteristics of Changsha area,makes statistics of the actual power demand of the airport substation area,forecasts the long-term power demand of the airport,and proves the necessity of building intelligent substation in this area.(2)The electrical part of the primary side of the airport 110 k V intelligent substation is designed.The outgoing line and the project scale of the airport 110 k V intelligent substation project are determined according to the load demand.After comparing the two connection modes,the expansion of the internal bridge and the single bus section connection are selected as the main connection mode of the substation,and the selection of the main transformer model is carried out.According to the thermal stability and dynamic stability required by the design manual,the The circuit breaker,disconnector and current transformer are selected.Through the improvement of the connection method of voltage transformer,the value of DC resistance and AC excitation impedance is increased,which can restrain the low-frequency oscillation and avoid the damage of transformer.Finally,the parameters of bus and station power supply are calculated.(3)This paper introduces the secondary structure of the intelligent substation,studies the relay protection architecture standard of the intelligent substation,divides the secondary equipment into modules,and then configures the three-layer network framework based on the transformer,merging unit,switch,intelligent terminal,etc.the setting calculation is carried out from the main transformer protection and line protection,and finally combined with the actual project,Taking the main transformer as an example,the connection mode is shown in the form of virtual terminal table,and the sending and receiving of goose and SV are shown in the graphical SCD visualization software.(4)According to the characteristics of outdoor 110 k V substation project,the prefabricated optical cable selection scheme is proposed to realize the "plug and play" function.Through the comparison of prefabricated optical cable connectors,the prefabricated outdoor optical cable of MPO type optical cable connector is adopted.Through the economic and technical comparison of the connection schemes of prefabricated optical cable inside and outside the prefabricated cabin,the optical cable exchange scheme is adopted.In this paper,based on the construction of intelligent substation,from the perspective of engineering practicability,through the use of advanced design technology in intelligent substation,the secondary system modular design of 110 k V intelligent substation is realized. |
