Abstract

The cause of a methodological error in the calculations of short-circuit currents as exemplified in the power supply of a traction network with two-way supply has been shown. It is to be noted that, in an actual power supply circuit, two adjacent traction substations are connected along the 110 (220)-kV lines by mutual resistance, whereas there is no such connection in the designed arrangement. On the basis of the designed scheme, a new equivalent circuit is formed, in which the resulting traction power circuit remains unchanged. The transformation of the initial circuit has enabled removing the error and calculating the short-circuit voltages in the traction network explicitly. Replacement of a symmetric three-phase external power supply system and a traction transformer with an equivalent single-phase circuit when calculating two-phase short-circuit currents in the traction network is shown to be viable. The validity of replacement of a symmetrical three-phase network for a single-phase one has been proved both by transformation of the three-phase equivalent circuit and by means of the equivalent generator method. It is established that, despite the difference in phase resistances of substations with Y/Δ and Y/Y transformer connection circuits, equations for determination of two-phase short-circuit currents prove to be the same.

中文翻译：

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双向电源牵引电源系统中短路电流的等效计算方案

摘要

短路电流的计算方法错误的原因已得到证明，例如在具有双向电源的牵引网络的电源中。要注意的是，在实际的电源电路中，两个相邻的牵引变电站通过互阻沿110（220）-kV线路连接，而在设计方案中没有这种连接。根据所设计的方案，形成新的等效电路，其中所得的牵引功率电路保持不变。初始电路的转换可以消除错误，并明确计算牵引网络中的短路电压。在计算牵引网络中的两相短路电流时，用等效的单相电路代替对称的三相外部电源系统和牵引变压器是可行的。通过三相等效电路的变换和等效发电机方法，已经证明了用对称三相网络代替单相电网的有效性。可以确定，尽管变电站的相电阻不同，Y /Δ和Y / Y变压器连接电路，用于确定两相短路电流的方程式证明是相同的。