Question

哪位大侠能帮我把这篇文章翻译成英文，毕业论文要用，急啊~~多谢各位了

不要是机器翻译的！Thank you !!!
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 路电流超标问题已成为困扰国内许多电网运行的关键问题。然而，在进行三相短路电流计算 时，各设计、运行和研究部门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断的差异，以及短路电流限制措施的不同。
如果短路电流计算结果偏于保守，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，在深入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，以及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。
1短路电流计算方法
经典的短路电流计算方法为：取变比为1.0，不考虑线路充电电容和并联补偿，不考虑负荷 电流和负荷的影响，节点电压取1.0，发电机空载。短路电流计算的标准主要有IEC标准和ANSI标准，中国采用的是IEC标准。国标规定了短路电流的计算方法、计算条件。国标推荐的三相短路电流计算方法是等值电压 源法，其计算条件为：①不考虑非旋转负载的运行数据和发电机励磁方式；②忽略线路电 容和非旋转负载的并联导纳；③具有分接开关的变压器，其开关位置均视为在主分接位置 ；④ 不计弧电阻；⑤ 35 kV及以上系统的最大短路电流计算时，等值电压源取标称电压的1 .1（计算中额定电压的1.05 pu），但不超过设备的最高运行电压。
对于电网规划、运行部门，三相最大短路电流计算是主要的计算内容。计算中，各电网、电 网内的不同部门可能采用不同的计算条件。差别主要集中在变压器变比、节点电压的选取上 。变压器变比有取1.0，有取实际运行变比的；节点电压可能取1.0，也可能取1.05。这两者 的不同组合均有所采用，显然，这将影响短路电流的计算结果。问题的根源在于计算人员往 往根据计算程序的固有设置来计算，而计算程序又缺乏足够的灵活性所致。其实，若了解短 路电流计算的要求，计算人员是可以对所得的计算结果进行适当的加工的。有的商业软件也 提供了灵活的短路电流计算条件设置功能。�
2影响短路电流计算结果的因素
美国PTI公司的PSS/E程序提供了基于潮流的短路电流计算和采用经典方法、ANSI标准或IEC 标准进行短路电流计算的选择。采用IEC标准时，允许用户任意设定短路电流计算的初值条 件。可设定的选项包括：①变比选择：1.0或正常变比；②考虑充电电容与否；③计及并联 补偿与否；④节点电压值；⑤发电机功率因素。为此，利用PSS/E程序对其自带的算例进行了不同初值设置条件对短路电流计算结果的影响分析。

Answer 1

Three-phase short-circuit meter.with is power system planning, design and operation of the calculation and analysis to work. At present, three-phase current short road condition has become a troubled many domestic electrical key problems. However, in the three-phase short-circuit current calculation, the design, operation and the calculation method of the research department adopts each are not identical, this may cause short-circuit current calculation results and the difference of the judgment of short-circuit current exceeds differences, and short-circuit current restrictions.
If the short-circuit current calculation results rather conservative, may cause unnecessary waste of investment, If you tend to be optimistic, the safe and stable operation of the system of catastrophic. Buried Therefore, in the research of short-circuit current calculation standard based on the different condition of short-circuit current calculation of short-circuit current calculation results for grid, and the influence of short-circuit current calculation and limit to provide more practical methods and ideas.
1 short-circuit current calculation method
Classic short-circuit current calculation method for: change than 1.0, do not consider lines and parallel compensation capacitor recharge, don't consider the impact load and load current node voltages, take the 1.0, generator racing. The standard of short-circuit current calculation are mainly IEC standard and the ANSI standard, China USES is the IEC standard. Owing to the short-circuit current calculation method and calculation conditions. The standard recommends three-phase short-circuit current calculation method is equivalent voltage source, its calculation method for: 1) does not consider the rotating load operation data and generator excitation way, 2 lines and ignore the rotating electrical load of parallel admittance, 3 the transformer has tap-changer and its position as the position in the Lord, Regardless of the arc resistance; (4) 5 35 kV short-circuit current calculation system, the maximum equivalent voltage source, the nominal voltage from 1 (1) in the calculation of the rated voltage of the contributions of pu), but shall not exceed the maximum operating voltage devices.
For power grid planning and operation department, three-phase short-circuit meter.with the biggest is main content of calculation. The grid computing, and electricity network in different departments may use different calculation conditions. Differences are mainly concentrated in transformer, node voltage selection. Transformer has taken 1.0, have taken more than the actual operation change, Node voltage may take 1.0, also may take contributions. These two different combinations are adopted, obviously, this will affect short-circuit current calculation results. The root of the problem is calculated according to calculation program to staff the natural Settings to calculate and calculation program and lack of flexibility. Actually, if you know a short circuit calculation and the requirement of personnel is calculated from the calculation results can be appropriately. Some commercial software also provides flexible short-circuit current calculation conditions setting function. enterprise
2 influence factors of short-circuit current calculation results
American PTI company PSS/E program provides short-circuit current calculation based on the trend of the classical method, and the ANSI standard or IEC standard of short-circuit current calculation. IEC standard, allows users to set arbitrary short-circuit current calculation of the initial value. Set of options include: (1) change than choice: 1.0 or normal variable ratio, 2 consider whether charging capacitance, 3 and parallel compensation or not, 4 node voltage, 5 generator power factor. Therefore, using PSS/E procedures for its own example with different initial conditions of short-circuit current calculation results of analysis