Simulation And Research Of The Influence Of Prime Mover And Governor On Low Frequency Oscillation Based On ETSDAC

Stability analysis of power system is the basis of ensuring safe and stable operation of the power system. Traditional dynamic stability of the power system is mainly focused on the deterioration of the automatic voltage regulator system damping terms. The speed control system is generally considered acting slowly and could hardly influence the power system’s low frequency oscillation characteristics in the electromechanical process, which leads to getting little attention in industry. That is to say the mechanical power is regarded as a constant in the analysis of electromechanical disturbance. However, with the population of Digital Electric Hydraulic control system, the governor’s response rate and dynamic performance gets greatly improved which make the influence on the dynamic stability of power system more and more obvious.Firstly, this paper analyzes the cause of the low frequency oscillation from the perspective of damping torque and introduces one solution which is generally applied to suppress low frequency oscillation. Secondly, mainly theoretically analyzing the influence of prime mover and governor on low frequency oscillation from the perspective of damping coefficient, including analyzing the steam turbine and steam turbine governor’s parameters’ influence on dividing radian frequency, and using particle swarm optimization to estimate the maximum dividing radian frequency of hydroturbine and hydroturbine governor which has comparatively many physical parameters. Thirdly, introducing the stability analysis method of four machines thirteen nodes system.This paper programs the state matrix of four machines thirteen nodes system and analyze eigenvalue, relevant factors, subsidence ratio and other relative parameters to forecast the influence of prime mover and governor on low frequency oscillation. Building the user-defined module of four machines thirteen nodes system based on ETSDAC to perform the simulation of small disturbance, which proves the theoretical analysis results. These system parameters are used to tune the control parameters of power system stabilizer to suppress low frequency oscillation. At last, the simulation of large disturbance is performed under the same parameters and operating state. The results indicate that the influence of prime mover and governor on low frequency oscillation should not be ignored apart from its relatively slow acting speed and different parameters could have different effects.