Study on a new power modulation strategy of HVDC to improve transient stability in China Southern Power Grid

Nowadays it becomes more serious to improve transient stability of power system as the grid is becoming larger and more complex gradually. This paper presents a new automatic real-time power modulation strategy of High Voltage Direct Current (HVDC) based on Extended Equal Area Criterion (EEAC) and Bang-Bang Control (BBC) strategy to improve transient stability of power system. The proposed strategy has taken into account the restraints on both amplitude of power flow change, and rate of change. This strategy is evaluated on the detailed electromagnetic transient simulation model of China Southern Power Grid (CSG) in the EMTDC/PSCAD software. Simulations with several faults in different places show that the proposed strategy contributes a significant improvement of the system transient stability after a large disturbance. Voltage dropping after the fault is an important factor that affects the control strategy effect.