Modeling the Trans Bay Cable Project as VSC with MMC design.pdf

1 Abstract — This paper introduces a model developed for modeling the steady-state and the dynamic behavior of the Trans Bay Cable Project as Voltage-Sourced Converter based on the Modular Multilevel Converter design. The model is intended for time domain simulations in an electromechanical simulation program with a balanced positive sequence network representation. Typical applications are transient stability studies and performance analysis of the HVDC link within a large scale AC network. The new developed model is validated against a much more accurate electro-magnetic model comprising all parts of the complex converter control and the protection circuits. Index Terms — HVDC Power Transmission, Transient Stability Model Development, Voltage-Sourced Converter, Modular Multilevel Converter Design I. INTRODUCTION The Trans Bay Cable Project is a new High Voltage DC (HVDC) power transmission project within the Pacific Gas Electric (PGE) transmission system establishing the first HVDC link delivering power into the city of San Francisco with successful commissioning in March 2010. The power direction is uniform from the Pittsburg converter station in the North-East of San Francisco to the Potrero converter station in the center of the city. The converter stations are connected by a 55 mile (88 km) submarine XLPE DC cable buried in the Suisun Bay, the San Pablo Bay, the San Rafael Bay, and the San Francisco Bay. The decision for an HVDC link in combination with a submarine cable results from the unique geographic location of San Francisco at the top of the San Francisco peninsula, which is also called Greater Bay Area. The corridor connecting San Francisco with the surrounding mainland is narrow and creates a bottleneck. Therefore, the number of transmission lines connecting San Francisco through this corridor to the electrical power system is extremely limited. However, the steadily increasing demand of electrical energy is