The Research Of Wide-Band Equivalent Application In Modeling Large Power Grid

At present the CSG company has the world’s largest RTDS（Real-Time Digital Simulator）with33Racks (unit). Theoretically, it can achieve the real-time simulation in hundreds ofthree-phase AC nodes and multi HVDC system. However, the scale of RTDS simulation issubject to the hardware restrictions because of the electromagnetic transient real-timesimulation characteristics. The RTDS model which is based on the previous500kV level can’tsatisfy the requirements of the precision of simulation. So the CSG company proposed asimulation study based on the220kV level. Considering the restrictions of hardware resources,the simulation scale of power grid must be simplified. Therefore, a new equivalent methodbased on the frequency dependent network equivalent (FDNE) has been put forward.This paper compared the RTDS hardware resource with the actual grid scale, and putforward the equivalent demand. It is the first time to apply FDNE to the large-scale networkmodeling. Unlike the homology equivalence method, FDNE is electromagnetic andelectromechanical transient hybrid simulation method. This paper will study the constructionof FDNE and interface theories of electromagnetic electromechanical transient hybridsimulation, and it also will introduce the way to get the impedance related to frequency.In IEEE39system, this paper analyze the single port and multiport FDNE in stabile andtransient performance, and make a conclusion that the performance of FDNE and the originalsystem is almost the same. FDNE is applied in the Yunnan and Guizhou220kV AC system inthe power grid modeling. Both the power grid steady analysis and transient analysis based onFDNE is studied in this paper, and it verified a good adaptability of FDNE in power systemmodeling. FDNE solved the contradiction between the hardware restrictions and thesimulation demand, which set a new research direction for power system modeling.