Operator Training Simulator: Component Models

The power system simulation in an operator training simulator (OTS) is made up of a periodic solution of the steady state power network synchronized with a solution of the slow dynamic behavior due to the power balance of the system. The periodicity of the static solution (henceforth, called the OTS cycle time) has to coincide with the data scan rate of a control center so that changes in the variables of the simulated system accurately mimics the actual measurement data acquisition system. Thus, if the computation time for one static solution and the dynamic solution for the cycle time, can be kept to less than or equal to the cycle time itself, then effective real time simulation is achieved. Obviously, a matching of the computer size to power system size is needed to ensure this real time simulation, assuming, of course, that the fastest available solution algorithms are used. The design of such a computationally demanding application as the OTS requires many considerations almost all of which distill down to a compromise between accuracy and computation. Thus, the models used to represent the various components of the power system have to be carefully chosen to provide adequate accuracy with the highest computational efficiency. Such models have been developed and refined over the years for such applications as power flow and transient stability. However, the requirements of an OTS are sufficiently different from these other applications that many of these existing models were not found to be directly usable without change.