Study on small signal stability of microgrids: A review and a new approach

Microgrid is an effective concept for distributed renewable energies connecting to utility grid. However, enormous challenges have also been brought into the microgrids study considering the intermittence, randomness characteristics of renewable energies. As a result, the power generations of distributed generators fluctuate frequently. Furthermore, it is difficult to obtain the parameters of microgrids accurately. Thus, the study on small signal stability of microgrids is especially important. This paper presents a review of exiting small signal stability methods for microgrids. Besides, a new approach based on Singular Entropy and Matrix Pencil is proposed. Meanwhile, its validity and effectiveness are confirmed by some examples compared with Prony algorithm. Then, the proposed method is also applied into a microgrid with an improved droop control strategy. Finally, a framework based on the proposed method for small signal stability, warning and emergency control online in microgrids is available. (C) 2011 Elsevier Ltd. All rights reserved.