| Power system stability is an important guarantee for the safe operation of the power system, the low frequency oscillation is an important factor affecting the stability of the power system. Wind power has randomness, intermittent, volatility and other characteristics, generally it locates in the weak links of the grid structure, large-scale wind power connecting the grid has brought new challenges for stable operation of the power system. The dynamic characteristics of the wind power different from traditional power will generate new effects on the low-frequency oscillation characteristics of the power system, energy storage is one of the best technology for this challenge, therefore, energy storage technology will play an important role in the future power system.This article considers suppression of a low-frequency oscillation type-forced power oscillation of double-fed induction generator connecting power network. First, we need build a simulation platform who contains wind power and energy storage:the wind farm is simulated with a equivalent DFIG, the model of energy storage SMES uses a third-order model. Basing on this simulation platform the analysis of small signal stability of power system with large-scale wind power. Taking into the volatility of wind power, this paper analyzes the influence of the changes of the wind farm and machine equivalent’s parameters for low frequency oscillation modes. According to the damping characteristics of the system, it designs a control method with energy storage and a damping control method basing on the input of synthetic power angle difference to suppress oscillation. Time-domain simulation results show that the control strategy can cope well with the fluctuation characteristics of wind farm output, and when the output and parameters of the wind farm change in a larger context, the controller designed is able to provide enough damping for the system, forced power oscillation of the contact line is curbed greatly. |
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