A Study On Short-circuit Current Limit Of Baotou Grid

The Baotou regional grid has much power source and the structure is close, and electrical distance between nodes is relatively close. So, in order to ensure reliability of power supply, multi-mode operation is taken into consideration, which causes the short circuit current level of Baotou 220kV power grid having been maintained at a high level. After the Baoxi 500kV substation puts into operatione, to control the short-circuit current levels, the double 220kV line circuit from Zhangjiaying to Zhizhaomiao will be disconnected. After the implementation of the program, the 220kV network short-circuit current level get some control, but remained at relatively a high level.To reduce the power of single-phase short-circuit current level of Baotou, consider to install a small reactance in neutral point of main transformer package of Baobei and Baoxi. Taking into account the fact of the installation of a small reactance project has been validated in the package, the small resistance installed the north main transformer neutral point is 15Ω. For ease of operation and management of the network, temporarily considering that Baoxi main transformer neutral point is also fitted resistance of 15Ω. After the installation of small reactors, including the Baobei and Baoxi 220kV single-phase short-circuit current side has been effectively controlled. The installation of a small reactance in neutral note can effectively reduce the network single-phase short-circuit current, but can’t do anything to control and reduce the three-phase short-circuit current. To the three-phase short-circuit current, network structure must be optimized and adjusted. Considering the fact Baobei and Weijun supply area, three-phase short-circuit currents of the 220kV side of Baobei and Gucheng, Shaerqin is at a high level, in order to reduce three-phase short-circuit current of the area. In the future year, the four main transformer point out, the short circuit current level has been effectively controlled, and is no more than the capacity of switchgear.