Small Signal Monitoring of Power System using Subspace System Identification

Aliakbar Mohammadi, Hamid Khaloozadeh, Roya Amjadifard


In this paper, small signal analysis of power systems is investigated using Subspace System Identification (SSI) methods. Classical small signal analysis methods for power systems are based on mathematical modeling and linearized model of power system in an especial operating point. There are some difficulties when such a classical method is applied, specially, in the case of large power systems. In this paper, such difficulties and their bases are investigated and in order to avoid them, it is suggested to use SSI algorithms for small signal analysis of power systems. The paper discusses extracting of small signal properties of power systems and presents some new suggestions for application of subspace system identification methods. Different types of subspace system identification algorithms were applied to different power system case studies using the presented propositions. The benefits and drawbacks of subspace system identification methods and the presented suggestions are studied for small signal analysis of power systems and power system monitoring. Several comparisons were investigated using computer simulations. The results express the usefulness and easiness of proposed methods.


small signal, subspace identification, power system, monitoring

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