Design and Application of Security and Stability Control System in Matiari-Lahore HVDC Transmission Project of Pakistan

With the operation of Matiari-Lahore HVDC, Pakistan power grid has been transformed from a 500kV pure AC grid to a hybrid AC and DC grid. With the change in the structure and scale of Pakistan power grid, there is an urgent need to analyze and study the security and stability characteristics of the grid. This paper analyzes the stability characteristics of the grid after a fault in Matiari-Lahore HVDC. It proposes stability control strategies for typical modes and each AC-DC power combination case. Based on the simulation analysis of the hybrid AC-DC grid in Pakistan, this paper presents the architecture of the security and stability control system (hereafter referred to as SSCS) to support the stable operation of the Pakistan power system. The operation mode of the security and stability control device (hereafter referred to as SSCD) is studied. The interface between SSCS and HVDC, control and protection system, is realized. The innovative SSCS was applied to the Matiari-Lahore HVDC transmission project to realize the DC fault matching cutter control strategy based on different operating conditions. At the same time, the research and application are significant to the design, development, and implementation of SSCS for other DC transmission projects.