外文资料Summary of power flow calculationPower system is calculated on the trend of steady-state operation of the power system as a basis, it's running under the given conditions and determine the entire system wiring in various parts of the power system running: the voltage of the bus, all components of a mid-stream power, The power loss, and so on. Power system planning in the design and operation of the existing power system in the form of research, we need to calculate the trend of using quantitative analysis of comparative power programme or operation mode is reasonable. Reliability and economy. In addition, the power flow calculation is calculated static and dynamic stability of the foundation of stability. So the trend is calculated on the power system of a very important and very basis of calculation. Power flow calculation also divided into offline and online calculation of two terms, the former mainly used for system planning and design and organization of the operation mode, while the latter is running for the system of regular monitoring and real-time control. The use of electronic digital computer to calculate the trend of the power system from the mid-1950s has already begun. Power flow problems in mathematical calculation is a group of diverse non-linear equations to solve the problem, its solution can not be separated from iteration. Therefore, the flow calculation method, it requires first and foremost a reliable convergence, and give the correct answers. As the power system structure and parameters of some of the features, and with the continuous expansion of the power system, the trend of increasing order of the equation, so the formula is not any mathematical method can guarantee is given the correct answer. This calculation of the power system to become a staff continue to seek new and more reliable way of the important factors.Use of digital computers in the power flow problems at the beginning, the general adoption of a node admittance matrix-based successive into the law. The principle of this method is relatively simple to compare the volume of digital computer memory, to the 1950s computer manufacturing level and then the power system theoretical level. However, it is convergence of the poor, when the system large-scale change, the sharp rise in the number of iteration in the calculation of convergence are often not the case iteration. This forced the staff to the power system to calculate impedance matrix-based successive into the law. Impedance method to improve the flow of the convergence of computing, the solution of the admittance system can not solve some of the trend, in the 1960s, access to a wide range of applications, has the power system design. Operational and research has made great contribution. At present, there are stillsome in the power industry units impedance method to calculate the trend. Impedance of the main shortcomings of the occupation of the computer's memory, each iteration of the large amount of calculation. When the system continue to expand, the more prominent of these shortcomings. 16 K memory of a computer in the use of impedance method can only be calculated at 100 following the system, 32 K memory of the computer can only calculate 150 nodes under the system. In this way, many of the power system in order to use impedance method shall not be first on the trend of the system is the streamlining of work. In order to overcome resistance in memory and speed of the shortcomings of the mid-1960s to the development of the impedance matrix-based Block impedance. This approach to a large-scale system divided into several small regional system, the computer only need to store various parts of the system impedance matrix contact line between them and the resistance, not only substantial savings in memory capacity, but also improve the Computing speed.Overcome the shortcomings of the impedance of hungry is another way to use Newton - Raphson method. This is the mathematics of nonlinear equations to solve the typical method, a better convergence. In resolving the issue of power flow calculation, is admittance matrix-based, therefore, as long as we can in the iterative process as much as possible to maintain the formula coefficient matrix sparse, and can greatly improve Newton's Law trend of the efficiency of procedures . Since the mid-1960s, Newton's law in the use of the best order of elimination, the Newton in convergence. Memory requirements. Speed all over the impedance, as the late 1960s after the widespread adoption of the excellent way.Flow calculation flexibility and convenience of the request, the application of digital computers is also a very key issue. In the past for a long time, the power flow calculation relies on the Taiwan exchange. Taiwan simulates the exchange of power systems, computing platforms in the calculation of the trend of the exchange, calculated at any time surveillance systems can run different parts of the state to meet requirements, if they run certain parts of unreasonable, you can make adjustments immediately. In this way, the equivalent of the process on the computing staff lost operating system. Adjustment process is very intuitive, physical concept is very clear. When the use of digital computers to calculate the trend when it lost this visual. To make up for this shortcoming, the trend of the establishment of procedures to the extent possible, in terms of computer calculation in the process of strengthening the process of the computer monitor and control, and to facilitate a variety of modifications and adjustments. Power flow calculation is not a simple calculation, to run it as a form of adjustment may be more precise. In order to get a reasonable run, often need to keep in accordance with the results, modify the original data. In this sense, the trend in the preparation of our program, the ease of use and flexibility must be sufficient attention. Therefore, in addition to the requirements in various ways to modify as muchas possible. Adjustment, we must pay attention to input and output of convenience and flexibility, strengthening human-computer links, so that the calculation of staff to monitor timely and appropriate calculations to control the conduct of calculation .Power flow calculation is a power system analysis of the most basic terms, the complex power system under normal and failure conditions steady-state running the calculation. The trend is calculated to strike a target in the power system to be running the calculation. That is, voltage and power distribution node, to check whether the components of the system overload. Voltage meets all requirements of the distribution and allocation of power is reasonable and the power loss, and so on. Of the existing power system operations and expansion, the new power system planning and design of the power system for static and transient stability of the trend are calculated as the basis. If the trend of the results available on steady-state power system, or estimate the optimal security, such as the trend of the flow calculation method and the model has a direct impact. The actual power system that the main trend of technology adoption Newton - Raphson method.In the management of the operation mode, the trend of power grid operation mode is to determine the basic starting point in planning areas, the need for trend analysis verified the reasonableness of the plan in real-time operating environment, dispatchers, provided the trend of End-expected operating conditions in the power grid To check the trend of operational reliability. In the power system dispatching a number of areas related to the trend of grid computing. Electricity network is to determine the trend of running the basic factors, the trend is steady-state power system on the basis and prerequisite .外文原文翻译电力系统潮流计算综述电力系统潮流计算是研究电力系统稳态运行情况的一种计算，它根据给定的运行条件及系统接线情况确定整个电力系统各部分的运行状态：各母线的电压，各元件中流过的功率，系统的功率损耗等等。