Electromechanical transient simulation of LCC HVDC

Abstract

The line commutated converter based high-voltage direct current (LCC HVDC) is widely used in power system to transmit a large amount of power for a long distance, which may have a great effect on the whole power system's stability. The LCC HVDC model has been modeled and simulated in detail in the electromagnetic simulation software [4-8] to ensure the accuracy of LCC HVDC itself. However, because of the great impact on the large scale of power system stability, the LCC HVDC should also be involved in the simulation of the whole system with an electromechanical model. The power system is always in three phases and symmetric in steady state. When the disturbance has happened, the electromagnetic process is usually finished in short term and the focus is changed to the power system stability, then the electromechanical simulation is employed. The electromechanical transient simulation [3] is focused on the reaction between electrics and mechanics, and is usually used for large-scale power system simulation, which is based on the hypothesis that the electric power system is symmetric, and the harmonics are not considered. The time step may be several mil-liseconds and the dynamic process may be extended to several seconds or minutes.