Research On Method With High Accuracy And ’A’Stablility Of Power System Transient Stability Calculation And Application

With the completion of HVDC transmission projects and HVAC system,the format of China’s ultra-large-scale interconnected power system is gradually formed. With the scale of the grid gradually expands, the power system stability problem is getting worse. In recent years, many large-scale blackout accidents shock us. Since the high-order Taylor series method is applied to determine the transient stability of power systems, the transient stability algorithm research that bases on the Taylor series has intensive study. This paper analyzes most recent studies in the application of Taylor series method in power system. Aim to the stability, accuracy and computational speed of Taylor series method, this paper studies the implicit Taylor algorithm which not only has the high precision but also is A stable.Research shows that the calculate accuracy of explicit Taylor series method is higher while the stability is poorer; the stability of the implicit Taylor series method is better, but the calculate accuracy is poor. In order to improve the numerical stability and accuracy of high-order Taylor series method, we research in the original implicit Taylor series method to study the regulation of its stability and accuracy. In order to improve the implicit Taylor series method numerical stability and can’t reduce the calculation precision, a new method that setting the proper values of the parameters is put forward. The method can not only keep the implicit higher-order Taylor series method A stable but also keep the calculation precision reach2N order when the Taylor’s expansion reaches N order.In order to improve the calculation speed of implicit tuned Taylor series method, variable step method is used. Implicit tuned Taylor series method has its own characteristics, that is, we should take the prospect approach to calculate the value Uk+1(0) of K+1in the right side of the equation. And then we can get the value of Uk+1(1) when taking advantage of the value of Uk+1(0) to correct it. The accuracy of the calculation method is much lower than the correct method. We achieve the variable step size method by analyzing the relationship between the truncation error of numerical method and the calculation of step and the relationship between truncation error and the step changes with time, focusing on characteristics of achieving the algorithm to estimate the truncation error of the method based on the difference of a "correct" value and "prospect" value. The advantage of this method is making full use of the characteristics of high-precision A stable implicit Taylor series method to design, and avoiding the extra massive calculation for implementing variable step in the process. During the process of programming the power system software, the graphics modeling technology and information sharing technologies are studied. Analysis the Common Information Model (CIM, Common Information Model) technology in IEC61970and the SVG (Scalable Vector Graphics) technology which came up by W3C. Put forward "holographic" modeling technology that regard the database as the core, and build models of the power system and the graphics system. This method stores the model data of power system and the corresponding graphic data in the database. The method can easily achieve data sharing.This paper studied the quick access technology based on Oracle database. Making researches in commonly used database access methods such as ADO, DAO and ODBC of Oracle database. Applying the OCI database technology in power systems to achieve quickly read and store. As for the database read operation, we use of an array bound read methods; as for database write operations, we use a direct path load method. After taking these two methods, the efficiency of the database to read and write and the calculation speed of power system computation software have been effectively improved.Take the2machines5buses system and a provincial network of72machine systems as examples to validate the implicit tuned Taylor series method and the implicit tuned variable step Taylor series method,using the programming software. The simulation results show that implicit tuned Taylor series method and implicit tuned variable stepaylor series method improve the accuracy of the calculation effectively besides ensure the stability of calculation; two methods has good adaptability, and can be used for long-term simulation; Implicit tuned variable step Taylor series method can at almost no additional calculation based on the dynamic control simulation step length, effectively improve the efficiency of the simulation computation.