Research And Implementation Of Real-Time Digital Simulation Method Of AC-DC Power System Based On RTDS

Because of the great advantagements of long distant and big capacity in electric power transimission, High Voltage Direct Current technology plays an important role in the Project of west-east electricity transmission and nationwide interconnection of Chinese power system. But it brings enormous impact to the safety and stability of the entire power grid. The dynamic characteristics of the AC-DC power system can be reflected accurately by electicmaganetic simulation tooles with the external actual DC control and protection devices. In this paper, an AC-DC real-time simulation system is established, four real faults have been successfully simulated, then the electromagnetic transient and electromechanical transient hybrid real-time simulation approach is proposed, and a complete simulation credibility evaluation theory is formed.The general principle of AC-DC power system simulation on Real-Time Digital Simulator (RTDS) is proposed in this paper. The key problems in modeling such as dynamic equivalent of AC power system and choice of simulation time step are introduced. And some measures are proposed to improve RTDS models. An AC-DC real-time simulation system platform is established.The equivalent model of a real power grid is built on RTDS. The playback approach of field fault recordings is developed. Four real faults have been successfully simulatedd by use of the simulation model of RTDS. The real causes of faults are analyzed, and some improvement measures are put forward. The simulation results are compared against the field fault recordings. It is demonstrated that the proposed simulation models are both precise and reliable. The RTDS model established in this paper can reflect the dynamic characteristics of the real power system accurately.Based on RTDS, this paper proposes an electromagnetic transient and electromechanical transient hybrid real-time simulation approach. And a real-time electromechanical transient simulation program is developed under CBuiler circumstance. The paper proposes the equivalent circuits between electromagnetic and electromechanical network, and then the hybrid real-time simulation platform is established. The validity and efficiency of the proposed hybrid real-time simulation approach are demonstrated by simulation casesIn this paper, residual similar index was used to characterize the global error of dynamic simulation, and then frequency, damping and amplitude similar indexes were employed to represent features error of transient signals respectively, which formed a complete simulation credibility evaluation theory. A calculation program for simulation credibility evaluation, which was developed by LabVIEW, was employed to analyze the theoretical current waveforms and results of fault simulations. Through simulation credibility analysis, the material quantitative index of simulation errors was obtained by which the credibility of simulation results was evaluated exactly and objectively and the numerical reference for the modifying of model parameters was provided. Simulation results has proved the validity of the proposed power system credibility evaluation theory.