Power flow calculation is to determine the steady-state operation parameters of each part of the power system according to the parameters and operating conditions of the given power grid structure, generators, loads and other components.
Significance and purpose of topic selection of MatlAB power flow calculation modeling and simulation opening report
Power flow calculation is the simplest but very important analysis and calculation in power system, which can be used to study various problems raised in system planning and operation. For the planned power system, power flow calculation can verify whether the proposed power system planning scheme can meet the requirements of various operation modes; For the running power system, it can be predicted by power flow calculation whether various load changes and network structure changes will endanger the safety of the system, whether the voltages of all buses in the system are within the allowable range, and whether various components (lines, transformers, etc.). ) will overload in the system, and what preventive measures should be taken in advance when overload may occur.
However, the traditional power flow calculation program lacks a graphical user interface, the results are not intuitive, it is difficult to integrate with other analysis functions, and the network raw data input is large and prone to errors. With the rapid development of computer technology, combined with the characteristics of power system and the development and design idea and overall structure of graphical power flow calculation software, the application of MATLAB software can improve this problem very well. The main features of the system are simple operation, intuitive graphical interface, stable operation and accurate calculation. In the calculation, the algorithm is improved to improve the calculation speed, and various types of effective encapsulation make the program have good modularity, maintainability and reusability.
Research status of the subject (including literature review)
Power flow calculation of power system is the basic operation to study the stable operation of power system, which can determine the voltage distribution and power distribution of the system, as well as the power distribution and loss in the network. For the planned power system, power flow calculation can verify whether the proposed power system planning scheme can meet the requirements of various operation modes; For the running power system, it can be predicted by power flow calculation whether various load changes and network structure changes will endanger the safety of the system, whether the voltages of all buses in the system are within the allowable range, and whether various components (lines, transformers, etc.). ) will overload in the system, and what preventive measures should be taken in advance when overload may occur.
Power flow calculation is not only the basis of quantitative analysis of rationality, reliability and economy of power system planning, design and operation mode, but also the basis of static and transient stability calculation of power system. Power flow calculation with electronic computers began in the mid-1950s. Gauss-Saidel iterative method based on node admittance, Newton-Raphson method, a typical method for solving nonlinear equations, and its improved method, PQ decomposition method, are experienced.
In recent 20 years, the research of power flow algorithm is still very active, but most of the research is carried out around the improved Newton method and PQ decomposition method. In addition, with the development of artificial intelligence theory, genetic algorithm, artificial neural network and fuzzy algorithm are gradually introduced into power flow calculation. However, so far, these models and algorithms can not replace Newton method and PQ decomposition method. The requirements of power flow calculation can be summarized as follows: (1) the reliability or convergence of the algorithm.
(2) Calculation speed and memory usage
(3) The convenience and flexibility of calculation. With the large-scale, strongly nonlinear and multi-component characteristics of power system becoming increasingly prominent, the amount of calculation and complexity of calculation have increased sharply, and the speed of the old computer software to deal with power flow calculation can no longer meet the simulation requirements of large-scale power grid simulation and real-time control. MATLAB is a commercial mathematical software produced by MathWorks Company in the United States. It is an advanced technical computing language and interactive environment for algorithm development, data visualization, data analysis and numerical calculation.
It is second to none in numerical calculation in mathematical science and technology application software. MATLAB can perform matrix operations, draw functions and analyze data, develop and implement algorithms, create user interface models, and connect programs and applications in other programming languages. With its language, tools and built-in mathematical functions, we can explore many methods to get results faster than spreadsheets or traditional programming languages (such as C/C++ or Java). MATLAB is widely used, including signal processing and communication, image and video processing, control system, test and measurement, computational finance and computational biology. In various industries and academic institutions, more than one million engineers and scientists use MATLAB as a technical computing language. MATLAB is a scientific computing language with powerful functions such as numerical calculation, symbolic operation and graphic processing.
MATLAB is a powerful computer software. When writing programs, MATLAB allows users to write programs in mathematical language, which is closer to the written mathematical expression format than BASIC and FORTRAN languages, and its programs are easy to debug. Under the same calculation requirements, using MATLAB programming will greatly reduce the workload. The method of power flow calculation using MATLAB language is simple in programming and efficient in operation, which accords with people's thinking habits. The calculation results can meet the needs of engineering calculation and verify the effectiveness of this method, which opens up a new idea for solving the power flow calculation problem of large power grid.
Subject content and research ideas
Newton-Raphson method and other commonly used power flow calculation methods are analyzed. Firstly, the mathematical model of power flow calculation is established, including the principle and calculation method of admittance matrix, the basic equation of power flow calculation, the node classification of power flow system and the constraint conditions of power flow calculation. Secondly, the basic principle, solution process and program block diagram of Newton-Raphson method are summarized. Finally, the matrix is generated and calculated by MATLAB software, Newton? Rafson method power flow calculation program. Newton-Raphson method is used to establish a simulation model from the prepared raw data, analyze the simulation results, and complete the design specification.
The emphases and difficulties of this topic.
The characteristics of modern power system, such as large system, strong nonlinearity and multi-components, are increasingly prominent, and its calculation amount and complexity increase sharply. Newton-Raphson method is an effective iterative calculation method for solving nonlinear algebraic equations. Newton-Raphson method needs a lot of numerical calculation. The determination method of self-inductance and mutual admittance, the properties of node admittance matrix, the equivalent circuit of non-standard transformer and the classification of power system nodes are all easily confused. In the design of MATLAB, the filling format of original data is a key link, which is directly related to the convenience and flexibility of program use. The amount of data input is large, so be careful, otherwise it will greatly increase the workload.
Thesis proposal
Summary of power flow calculation in power system
1. 1 Brief introduction of power supply system
1.2 introduction to power flow calculation
1.3 Significance and development of power flow calculation
2. Mathematical model of power flow calculation.
2. Principle and calculation method of1admittance matrix
2. 1. 1 Determination method of self-inductance and mutual admittance
2. Properties and Significance of1.2 Node Admittance Matrix
2. 1.3 equivalent circuit of nonstandard ratio transformer
2.2 Basic equations for power flow calculation
2.3 Power system node classification
2.4 Constraints of Power Flow Calculation
3. Overview of Newton-Raphson method
3. The basic principle of1Newton-Raphson method
3.2 Newton-Raphson method solving process
3.3 Newton-Raphson method program block diagram
4.MatlAB modeling and simulation.
4. Introduction to1MATLAB
4.2 Generation of Matrix
4.3 Matrix operation
4.4 Newton? Rafson method power flow calculation program
4.5 Result analysis
abstract
Schedule (including time division and main contents of each stage)
Names and dates of each stage of serial number design (teaching week)
1. Distribute the task book, retrieve and collect the latest information of the project, and investigate and analyze 20141.7? 165438+ 10/3
4. Provide the opening report 20141014? 165438+1October 22nd
3. Revise the foreign translation materials related to the opening report 2014165438+1October 22nd? 65438+February 28th
4. According to the opening report, conduct mid-term inspection and write the first draft of the paper 20 15 1? March 2005, 65438
5. Revise the paper according to the tutor's opinion, complete the paper and hand it in on March 20 15. 15? April 18
6. Instruct the teacher to evaluate the results, and the teacher will mark the paper 2015 April 18? April 30th
Graduation defense 2065438+April 30, 2005? May 16
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