Operator Training Simulator: Algorithms and Test Results

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 (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. The design of such a computationally demanding application requires many considerations almost all of which distill down to a compromise between accuracy and computation. A companion paper describes the models developed to obtain the required accuracy for such a simulation. This paper describes the algorithms developed to meet the computation times required for real time simulation. In a control center, the data acquisition system is usually designed to scan different classes of data at different scan rates. Although every system is different in detail, the AGC data (generator powers and tie-line flows) scan is the most frequent, typically around 4 seconds. This implies that the OTS cycle should be at least as fast as the AGC scan cycle. To achieve this on the size of computers normally used in control centers (it can obviously be done on faster processors) has been difficult for system sizes of say, 1000 buses. The main hurdle has been the simulation just following a large disturbance.