曲折型接地变压器容量选择

Select the Capability of Interstar Grounding Transformer

随着电力负荷的迅速增长,城市电网建设规模不断扩建和延伸,受城区规划、环保和场地等条件制约,市区变电所越来越多地采用电缆馈线,10 kV系统单相对地电容电流大幅度增加。然而城市变电所主变压器10 kV侧为三角形接线,无中性点引出,形成人为中性点经小电阻接地,就需配置ZN型接线的接地变压器。本文对城市电网10 kV系统中曲折变容量选择问题进行了分析,并系统地介绍了三种不同用途的曲折变容量选取方法。

With the power load＇s rapid growth, the urban power grid construction scale＇s continual extension, the urban transformer has to provide cable feeder, and lOkV system single - phase ground capacitance - current increases. However the main transformer＇s 110kV side of urban substation is the triangle connection, no netural point, and forms man- made netural point by small resistance grounding, configuring ZN type connection＇s grounding transformer. The paper analyses the choice problem of lOkV interstar transformer＇s capacitance, and introduces three differ purpose＇s choice capacitance method of interstar transformer.