Advanced Hybrid SFA/EMTP Simulator for Seamless Integration of Power Systems Dynamics and EMT Transients

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It is expected that for the year 2050, 70% of the total electrical energy in the world will be based on wind and solar. This continuously increasing amount of Inverter Based Generation (IBG) is weakening the equivalent mechanical inertia of traditional large hydro and thermal synchronous generators and the ability of the power system to ride through normal system dynamics. Traditional power systems analysis software for steady state and dynamic system operation, such as power flow, transient and dynamic stability, and voltage and frequency stability, are based on phasor analysis for the electrical system and solving the electromechanical equations for the generators. This approach is valid under the assumption of high mechanical inertia that brings the system time constants to the order of the milliseconds for faults and switching actions, or seconds for load/generation governor control. However, with the penetration of IBGs and the decrease of the system's mechanical inertia, the disturbances in the steady state operation will give rise to stronger deviations in angle, voltage, and frequency, and the limits imposed by the system regulators and the settings of the system relays will need revisions. On the other hand, the solution of the IBG subsystems and other power electronics equipment that interact with the AC grid is normally done with EMT software that works in the range of the microseconds. Strong efforts are currently being made to integrate phasor solutions with EMT solutions. However, because of the conceptual and numerical difficulties involved in interfacing two systems of different nature, with different solution methods, and different integration steps, fundamental research into these issues is needed for developing general purpose simulation software that can seamlessly integrate an arbitrary number of subsystems modelled with phasor or EMT methods. The main motivation of the work in this proposal is to find better solutions to the issues of interfacing phasor and EMT systems that improve on or remove the current limitations. We want to develop general solutions that can join seamlessly any number of subsystems represented as phasor or EMT, without having to use iterations, reduced equivalents, or buffer zones. A number of numerical and fundamental conceptual issues have to be addressed to achieve these objectives. The NSERC Discovery grant is the apropriate grant in Canada to supports the fundamental research needed to achieve these breakthroughs. The impact of these solutions is far reaching in the power systems community as industry makes its transition from a fundamentally 60 Hz system to a hybrid system.