A Study of Cable Models as an Interface for Connecting Real-Time Simulators for Large Electrical System Simulations

Abstract:
To prevent critical situations in future power grids, it is planned to perform interaction studies before connecting large power-electronic based generation units such as offshore wind farms to the grid. One possible approach to carrying out large electromagnetic transient (EMT) studies is to set up a distributed simulation on multiple real-time simulators (RTSs). This paper investigates the possibility of using models of submarine cables as a software interface for connecting two RTSs. In this context, the similarity between the finite propagation time of currents and voltages along longer lines and typical sampling times of simulators can be exploited. A method of using Bergeron’s cable model to couple individual wind turbines in an offshore wind farm is demonstrated and the necessary requirements are discussed. In addition, the possible effects of asynchronous operation of the simulators are described. The results are compared to the solution of the transmission line equation in the frequency domain as a test of accuracy. Finally, simulation results are used to illustrate the concept.