High-Voltage Substation Outlet Scale Study for Large Receiving End Networks

With the growth of high-voltage substations in the receiving end grid and the tight connection between the regional power grids, the short-circuit current level of the high-voltage bus has been increasing year by year. The number of distribution lines of highvoltage substations and the distance between them are important influencing factors for the short-circuit capacity of the bus side, which is an important parameter to be considered during grid planning. By summarizing and analyzing the structural characteristics of the typical 500kV, 750kV large receiving end power grids in North China, East China, Central China, and Northwest China, and taking into account the number of substations, the distance between stations and voltage levels, an equivalent circuit model of the whole power system is constructed with the high-voltage substations in large receiving end power grid as the base point. By analyzing the model of the grid's high voltage side with typical parameters, combining the circuit breaker interrupting capacity level and the number of substations, the reference range of the number of substation outgoing lines is determined, and it is proposed that the reasonable outgoing line scale of the high voltage substation is six lines in most cases. Finally, the short-circuit current levels in the State Grid verified the feasibility and validity of the proposed high-voltage substation outlet size of the receiving-end grid.