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This paper presents a novel approach to dynamic phasor-based transient stability simulation. The proposed method is based on the modified nodal analysis (MNA) approach to circuit simulation, which is used to construct continuous differential-algebraic equations (DAEs). The proposed method makes use of the stamp technique, which makes it possible to construct a general purpose MNA-based simulator. Stamp-based models for common power system components are derived in this work. A new MNA-based synchronous machine model is presented, which represents machines as nonlinear inductances instead of subtransient equivalents. The resultant continuous DAEs are numerically solved using the general purpose variable step and variable order library \texttt{IDA}. Simulation results from the IEEE 68 bus test system, a real 400 bus power system, and the IEEE 39 bus test system with an embedded HVdc transmission system demonstrate that the proposed method is suitable for large ac networks with power electronic devices. The results demonstrate good agreement between the proposed method and electromagnetic transient (EMT) simulation. The results also demonstrate that the proposed method is fast and scalable with CPU times that are up to 200 times faster than EMT simulation.

The modular multilevel converter (MMC) has become a widely used topology for voltage source converter–based high‐voltage direct current transmission projects. To calculate the power operation region of an MMC directly and efficiently, we propose a novel steady‐state phasor model of the MMC. The model is expressed as an equivalent capacitance in series with a voltage source, where parameters are independent of alternating current (AC) electrical quantity. Based on the model, we propose an open‐loop approach to determine the operation region boundary of MMC by calculating the envelopes of the P–Q curves. The effect of MMC parameters, the circulating current control, and the short‐circuit ratio of the AC grid to the power operation region can be determined by the size and position of the power operation region. The proposed approach and analysis results were verified by an MMC/AC simulation model built in PSCAD/EMTDC.

Generation of electricity using renewable sources of energy will be the only option available to us soon. This may happen within the next two decades. In the meantime, we make the transition form traditional synchronous generator driven power systems to fully renewable energy-based power systems where the energy source is integrated through power electronics converters. We must start thinking in a new way. This presentation will address the technological challenges associated with connecting renewables to the grid through converters and the options available to meet those challenges. While the ability of the converters to respond fast is an obvious advantage, unlike the synchronous generator, it does not have a rotating mass that stores kinetic energy. The short-term overcurrent rating of the converter is much less than that of a synchronous generator unless the converter is overdesigned. Addressing these engineering challenges will be discussed in the presentation.