"Efficient Modeling of Modular Multilevel HVDC Converters (MMC) on Electromagnetic Transient Simulation Programs"
Udana Gnanarathna (Ph.D. student)
Supervisor: Dr. Aniruddha Gole
Description of Project
The recent introduction of a new converter topology, the modular multilevel converter (MMC), is a major step forward in voltage sourced converter (VSC) technology for high-voltage high-power applications. To obtain a multilevel ac output waveform, a large number of semiconductor switches has to be used in the converter. The number of switches in MMC for HVDC transmission is typically two orders of magnitudes larger than that in a two or three level VSC. The large number of device count creates a computational challenge for electro-magnetic transients (EMT) simulation programs as it significantly increases the simulation time. In this research, an efficient, time-varying Thévenin's equivalent model was developed for the MMC converter based on partitioning the system's admittance matrix. The PSCAD/EMTDC simulation results shown that the model can drastically reduce the computational time without loss of accuracy. This approach enables what was hitherto not practical: the modeling of large MMC based HVDC systems on personal computers. Therefore, the use of the proposed method is demonstrated by simulating a point-to-point MMC-based HVDC transmission system successfully with more than 200 levels.
Accepted/Published Papers
1. U.N. Gnanarathna, A.M. Gole, and R.P. Jayasinghe, "Efficient Modeling of Modular ultilevel HVDC Converters (MMC) on Electromagnetic Transient Simulation Programs", IEEE Trans. on Power Delivery, Vol. 26, Issue 6, Jan. 2011. FULL TEXT
2. U.N. Gnanarathna, S.K. Chaudhary, A.M. Gole, and R. Teodorescu, "Modular Multi-level Converter Based Hvdc System for Grid Connection of Offshore Wind Power Plant", 9th International Conference on AC and DC Power Transmission, IET London UK, 2010 Oct. FULL TEXT
3. U. N. Gnanarathna, A. M. Gole, and S. K. Chaudhary, "Multilevel Modular Converter for VSC-HVDC Transmission Applications: Control and Operational Aspects", 16th National Power Systems Conference, NPSC-2010, Hyderabad, India, 2010 Dec.
4. U.N. Gnanarathna, A.M. Gole, A.D. Rajapakse, and S.K. Chaudhary, "Loss Estimation of Modular Multi-Level Converters using Electro-Magnetic Transients Simulation", International Conference on Power System Transients, IPST-2011, Delft, The Netherlands, 2011 Jun.