Study Of Dynamic Equivalent Of Power System Based On Parameter Identification

The dynamic equivalent of power system is widely used in modern power systems, because it may not only be able to reduce the workload of modeling and calculating, but also can highlight the main features of the systems. Coherency-Based Equivalent and Model Equivalent can only be used when the structure and component parameters of the power system are all known, and mainly used in off-line analysis of power systems. While, when the structure and component parameters of the power system are unknown, or the power systems operating conditions are changeable, the Estimation Equivalent can be used, needing dynamic response information of the system. Practice, the operation mode and the system structure and parameters and operating conditions of electric power system are changing. So the Estimation Equivalent based on parameter identification is a practical method. Just so, Estimation Equivalent is worth studying. The main work of this paper is as following.Firstly, this paper gives the concept of dynamic equivalent and its important application in the power system, and briefly describes the development and research status of dynamic equivalent, then analysis some important aspects of the application of dynamic equivalence in practical application.Then, this paper gives dynamic equivalent model structure of power system, including single connect-line regional dynamic equivalent model and multiple connect-line regional dynamic equivalent models. And gives the equivalent model structure, that is the equivalent generator, load model and their equations. In addition, the paper analysis the identifiability of the equivalent model structure's parameters.Then, this paper briefly introduces the identification method- Particle swarm algorithm, and discusses the application of PSO in dynamic equivalent, and the paper also gives the program process of dynamic equivalent based on parameter identification. The parameter identification results of signal machine system shows the accuracy of the program.At last, this paper mainly research the dynamic equivalent method based on parameter identification. And this paper do the equivalent simulation, taking the IEEE four machine-two areas system as a single connect-line regional equivalent calculation example and a 38 buses system as a multiple connect-line regional equivalent calculation example. And the paper also discuss the different equivalent results when setting up different fault and the response effect between the two system when using the equivalent models, and the analysis results show that this method is effective and the equivalent models can be used in common analysis of power systems.