各类预想事故情况下500kV终端站和枢纽站转供负荷能力定量对比

Comparison of Load Transfer Capacity Between 500 kV Terminal Substation and Hub Substation Under Various Expected Accidents

500 kV终端站的供电可靠性体现为各类事故情况下对下级负载的转供能力上,转供能力越大,减供负荷就越小,损失就越少。基于深圳城中心区电网现代片区即将新建的500 kV皇岗站这一规划年变电站,采用BPA软件分别计算加强和不加强220 kV线路联络时,各种预想事故下终端站和枢纽站的线路潮流,对比两者线路电流占额定电流的比例、线路电流占额定电流比例的变化率、负载率、负载率变化率。由此判断出加强220 kV线路联络后两者的差距比不加强220 kV线路联络时两者的差距有所减小,进而得出加强220 kV线路联络对提高500 kV终端站转供负荷能力具有一定的贡献,为500 kV终端站在城中心区的建设应用和采用加强220 kV联络的方法提高其供电可靠性提供数据支撑。

The power supply reliability of the 500 kV terminal station is reflected in the transfer capacity for lower loads in various accident situations.The greater the transfer capacity,the smaller the reduced load and the less the loss.Based on the planned annual substation of the 500 kV Huanggang Station to be built in the modern area of the power grid in the central area of Shenzhen,BPA software is used to calculate the line flow of the terminal station and the hub station under various expected accidents when the 220 kV line connection is strengthened and not strengthened respectively.The ratio of the line current to the rated current,the rate of change of the line current to the rated current,the load rate,and the rate of change of the load rate are compared.Therefore,it can be judged that the gap between the two after strengthening the 220 kV line connection is smaller than that when the 220 kV line connection is not strengthened.Then it is concluded that strengthening 220 kV line connection has a certain contribution to improving the load transfer capacity of 500 kV terminal station,and provides data support for the construction and application of 500 kV terminal station in the central area of the city and improving its power supply reliability by strengthening 220 kV connection.