The Research On Digital Simulation Platform For Active Distribution Network Based On RT-LAB

With the increasing of the distributed energy resources(DER) integrated into grids, conventional distribution network system faces many challenges. The one-way flow of passive distribution network(PDN) will gradually be replaced by two-way active distribution network(ADN). Active control regime makes it efficient for distribution network to absorb large-scale DER power, it is an advanced development stage of the distribution network.Digital simulation is an important and commonly tools to study the static and dynamic behavior of power system. Given the development status of ADN and difficulty of engineering application project to carry out, due to high costs, it's hard to obtain experimental data. Therefore, the research on digital simulation platform of ADN with DER and BESS have important theoretical and practical significance.Firstly, this paper reviewed development and research status of ADN, including effects of DG on distributed networks, energy storage system(ESS) mechanism and its applications in wind farm. After summarizing concepts and operation procedure of synthesized load modeling for distributed network, this paper presented network topology and control strategy of ESS for smoothing wind power fluctuations and frequency regulation. Then the model simulation process flow by RT-LAB is put forward, the method to build custom modules by S-function and the custom component library is conducted to study tools and approaches for development environment.Secondly this paper analyzed principle and process of designing the platform, as well as system architecture. The function and demand analysis of platform is demonstrated. Then this paper put forward and tested the format of back-end database and the method to communicate between platform, recognition program and database.The platform uses MATLAB to build simulation model, develop platform user interface, uses VC++to program recognition algorithm and use SQL Server 2000 as back-end database server. Modular software design and several interface technologies is used to bring all units into a whole.Platform features are as follows:firstly, custom library operation for different types of devices, including DER, ESS, power conversion system and networks system, such as building, packing, adding, updating and deleting components. In the second place, system simulation operation, such as build ADN simulation model building. Thirdly, simulation experiment, including real-time data demonstration and transient simulation experiments under the circumstance of steady-state conditions and fault disturbances. Furthermore, data process, such as intercepting data for identification, as well as importing, querying, displaying measurements or experiments data. Fourthly, model identification, including selection of identification data, model structure and identification algorithm. At last, ESS application, simulation experiments is carried out for power tracking, single energy storage system and hybrid energy storage system(HESS) smoothing wind power fluctuations, and primary frequency regulation and secondary frequency regulation.Given its advantage of open source code, stable structure, the platform provide a good experimental research tool to study impacts of ADN on comprehensive load characteristics of distribution network and BESS applications.