Hybrid simulation for long term dynamics

This paper describes the work done under the EPRI RP908-1 project to study the long-term dynamics of power systems using hybrid simulation. A hybrid simulator was designed, constructed and tested at the University of Missouri-Columbia for a sample system provided by General Electric in RP907-1. The sample system consists of 16 machines and 68 buses. Each power system component was implemented in electronic integrated circuits and is contained on 8" × 10 1/2" printed circuit cards. The power system model is an ac, single phase, variable frequency, simulation scaled to operate 20 times faster-than-real-time. The base frequency is 1200 Hz which means that a 20 minute real time run can be obtained in one minute system running time. A 16-bit digital minicomputer was used for input, output and control of the analog simulation. A special purpose digital/analog interface controller was designed and built to achieve the desired data collection and control functions. The analog power system models include all of the specific components which influence the long term dynamics. A description of the hybrid simulator, and the results of the specific studies performed are presented. Two scenarios demonstrating the long term analysis capability of the simulator are presented along with a comparison of short-term results with a conventional digital program. This project has successfully demonstrated the basic feasibility of the hybrid approach to perform long-term dynamics studies and has demonstrated a working model of a faster-than-real-time hybrid simulator. Furthermore, it was shown that the hybrid approach is feasible and practical for a wide range of additional studies and purposes.