Application of unknown input observers to locate forced oscillation source

摘要

In this paper, the problem of locating forced oscillation source at device level is addressed, using unknown input observer (UIO)-based method to realize oscillation source isolation. Firstly, a linear power system model suitable for oscillation source detection and isolation is derived. Typical oscillation sources, namely, oscillation sources from prime movers and speed governors, excitation systems, are included in the model as unknown inputs. Then, a systematic method using UIOs and fault isolation scheme to locate oscillation source is proposed. Using the disparities between the model responses generated by UIOs and the recorded responses, the proposed method establishes a one-to-one relationship between a residual and an oscillation source. The location of oscillation source at device level is accomplished on the basis of the different sensitivities of residuals to oscillation sources from different devices. The detectability of oscillation source and the numerical check are also discussed. The effectiveness of the proposed location method is verified by several simulation examples. The results show that the location of oscillation source by the proposed method is effective and is accurate to control the device that the oscillation source originates from.