LCC-HVDC System Dynamic Phasor Modeling Based on Improved Switch Function

Accurate modeling and dynamic simulation of integrated AC/DC grids play a fundamental role in power system stability analysis and control. Unbalanced operating conditions in AC side results in a large number of second harmonic current or voltage distortion on DC side and third harmonic on AC side. In this work, we build an advanced dynamic phasor model for the LCC-HVDC converter, which is suitable for the normal operating and unbalanced fault conditions of the system. Meanwhile, a second-order dynamic phasor model is proposed for the control system modeling and DC line. Finally, the proposed models are applied to the first CIGRE HVDC benchmark system to test the new model's validity. The simulation results are validated by PSCAD/EMTDC.