Comparative Analysis of Virtual Inertia Techniques in Wind Energy

Recent decades have seen an incline in integration of wind energy in to power systems across the world. This invariably leads to lower share of conventional power plant which subsequently reduces the grid’s inertia as a consequence of the decoupling rotational mass of the variable speed turbines and grid through power electronic converters. Accordingly, the overall system inertia is lowered leading to more frequent and intense frequency variations concomitant with the variation in the load. This research focuses on alleviating the rotational mass and inertia related problems caused by increasing wind power integration by adding an inertial loop to compensate the impact of frequency deviations due to abnormal transient conditions. The virtual inertia, thus added, reduces maximum rotational speed deviation while at the same time making the system slower and more oscillatory. The simulation consists of addition of synchronous generator capable of adapting its power output to the fluctuations in grid loads. A load step has been added for analyzing the performance improvement of the system as a result of the virtual inertia addition. The simulation has been modeled in Simulink MATLAB. The addition of the inertial power results in the improving the frequency drop from 58.42 to 59.31 Hz. This stabilization of 0.9 Hz carries a lot of significance for improving grid stability. In addition the angular speed of the turbine has also been enhanced as a result of the virtual inertia. These findings will prove extremely helpful in offsetting the drawbacks of greater wind energy addition to grid. The analysis needs to be further replicated with other transient conditions before being implemented in the grid.