• Identifying the key converter port admittance that has the greatest impact on the system stability. • Proposing a stability improvement method based on quantitative reshaping of the key converter port admittance. • Achieving a quantitative increase in the phase at the oscillation frequency of critical eigenvalue. The decentralized integration of large-scale renewable power generation (RPG) into the grid introduces complex interactions that are prone to small-signal instability due to impedance mismatch characteristics. To address this issue, a small-signal stability improvement method for the multi-infeed system with RPG based on quantitative reshaping of the converter port admittance is proposed in this paper. Firstly, using the small-signal model of the multi-infeed system, the sensitivity of the system eigenvalues with respect to the converter port admittances is calculated. This realizes the quantitative analysis of the degree of influence exerted by each converter port admittance on the system stability, thereby identifying the key converter port admittance that has the most significant impact on system stability. Next, by combining the admittance sensitivity with the correction amount of the system eigenvalue, the optimization value of the key converter port admittance is calculated. Then, a voltage feedforward combined with a band-pass filter is adopted to introduce virtual damping, thereby quantitatively reshaping the admittance of the key converter. Thus, the targeted improvement method achieves small-signal stability improvement of the multi-infeed system. Finally, the experiments validate the effectiveness of the proposed stability improvement method. © 2017 Elsevier Inc. All rights reserved.
Si et al. (Fri,) studied this question.