通常，三相短路电流最大，当短路点发生在发电机附近时，两相短路电流可能大

通常，三相短路电流最大，当短路点发生在发电机附近时，两相短路电流可能大于三相短路电流；当短路点靠近中性点接地的变压器时，单相短路电流也有可能大于三相短路电流。<br>1、先计算各电源到短路点的转移电抗（在某基准容量为基准值下的标幺值表示）；<br>2、换算成各电源容量为基准值的计算电抗；<br>3、各电源容量除以各计算电抗，即为各电源在短路点的短路电流；<br>4、上述各短路电流相加，即为总的短路电流（次暂态值）。<br> 三相短路电流计算是电力系统规划、设计、运行中必须进行的计算分析工作。目前，三相短路电流超标题目已成为困扰国内很多电网运行的关键题目。然而，在进行三相短路电流计算时，各设计、运行和研究部分采用的计算方法各不相同，这就有可能造成短路电流计算结论的差异和短路电流超标判定的差异，以及短路电流限制措施的不同。<br> 假如短路电流计算结果偏于守旧，有可能造成不必要的投资浪费；若偏于乐观，则将给系统的安全稳定运行埋下灾难性的隐患。因而，在深进研究短路电流计算标准的基础上，比较了不同短路电流计算条件对短路电流计算结论的影响，以期能为电网短路电流的计算和限制提供更切合实际的方法和思路。

通常，三相短路电流最大，当短路点发生在发电机附近时，两相短路电流可能大于三相短路电流；当短路点靠近中性点接地的变压器时，单相短路电流也有可能大于三相短路电流。<br>1、先计算各电源到短路点的转移电抗（在某基准容量为基准值下的标幺值表示）；<br>2、换算成各电源容量为基准值的计算电抗；<br>3、各电源容量除以各计算电抗，即为各电源在短路点的短路电流；<br>4、上述各短路电流相加，即为总的短路电流（次暂态值）。<br> 三相短路电流计算是电力系统规划、设计、运行中必须进行的计算分析工作。 目前，三相短路电流超标题目已成为困扰国内很多电网运行的关键题目。 然而，在进行三相短路电流计算时，各设计、运行和研究部分采用的计算方法各不相同，这就有可能造成短路电流计算结论的差异和短路电流超标判定的差异，以及短路电流限制措施的不同。<br> 假如短路电流计算结果偏于守旧，有可能造成不必要的投资浪费；若偏于乐观，则将给系统的安全稳定运行埋下灾难性的隐患。 因而，在深进研究短路电流计算标准的基础上，比较了不同短路电流计算条件对短路电流计算结论的影响，以期能为电网短路电流的计算和限制提供更切合实际的方法和思路。

Generally, the three-phase short-circuit current is the largest. When the short-circuit point occurs near the generator, the two-phase short-circuit current may be greater than the three-phase short-circuit current; when the short-circuit point is near the neutral grounded transformer, the single-phase short-circuit current may also be greater than the three-phase short-circuit current.<br>1. First, calculate the transfer reactance from each power supply to the short-circuit point (unit value representation under a reference capacity as the reference value);<br>2. Calculated reactance converted to the reference value of each power supply capacity;<br>3. The capacity of each power supply divided by each calculated reactance is the short-circuit current of each power supply at the short-circuit point;<br>4. The sum of the above short-circuit currents is the total short-circuit current (sub transient value).<br>The calculation of three-phase short-circuit current is a necessary work in the planning, design and operation of power system. At present, the problem of three-phase short-circuit current exceeding the standard has become a key problem that puzzles the operation of many domestic power grids. However, in the calculation of three-phase short-circuit current, the calculation methods used in each design, operation and research part are different, which may cause the difference of short-circuit current calculation conclusion, the difference of short-circuit current exceeding standard judgment and the difference of short-circuit current limiting measures.<br>If the calculation result of short-circuit current is conservative, it may cause unnecessary investment waste; if it is optimistic, it will cause disastrous hidden danger to the safe and stable operation of the system. Therefore, based on the deep research of short-circuit current calculation standard, this paper compares the influence of different short-circuit current calculation conditions on the short-circuit current calculation conclusion, in order to provide more practical methods and ideas for the calculation and limitation of short-circuit current in power grid.<br>