Small signal stability of weak power system integrated with inertia tuned large scale wind farm

The effective inertia of the power system would reduce if the penetration of variable speed wind farms (WFs) increases. The case becomes more serious in a weak grid, which can cause instability issues. As a result, WFs are usually required to provide inertia response by some grid codes. This paper analyzes small signal stability (SSS) of the weak power system connected with the inertia tuned WF based on systematic nonlinear simulations and modal analyses. As indicated in this paper, the inertia tuned WF improves the frequency response of the system. At the same time, the WF remarkably engages in the power oscillations and induces a new critical oscillation mode, which threatens SSS of the system. To avoid the instability problem, a cost-effective damping controller based on the local signal is also proposed for the inertia tuned WF. The simulation results show that the controller can help to stabilize the system without affecting the frequency support capability of the WF.