Faster-than-Real-Time Simulation of a Large Brazilian AC/DC Grid to Analyze Electromagnetic & Electromechanical Transients as Well as Commutation Failures

Power system studies consist mainly of power flow, short circuit, electromechanical transient (stability EMS) and electromagnetic transient (EMT) studies. EMS simulations are usually performed at the planning stage and by system operators using phasor methods to accelerate the analysis of very large systems under several fault contingencies. EMT analysis is performed with very detailed models and small integration steps to simulate fast transients and control dynamics. Determining the risk of multiple HVDC commutation failures and the resulting power transfer capability of large multi-infeed HVDC inverter systems would normally require performing EMT simulation using detailed HVDC controller models. However, using traditional singleprocessor EMT software is normally not practical to analyze the EMS of large systems with several HVDCs due to the long calculation times. This paper analyzes the performance of parallel EMT software to analyze the transient stability of practical and large AC/DC systems using standard multi-core computers. It will be demonstrated that a simulation speed of two real-time speed can be achieved with a reasonable number of processors, even for a system as large as the Brazilian grid.