Analysis of Low Frequency Oscillations Observed during a Power System Restoration Test

The power system restoration tests are essential processes to guarantee the effectiveness of the national restoration plans and to verify the performance of all the components belonging to the restoration backbone. During these tests, the portion of the grid involved in the restoration process operates whereas the rest of the grid maintains the normal operation. In this scenario, the transmission grid could affect the behaviour of the restoration backbone due to the electromagnetic-coupling between two overhead lines installed in the same tower. In this paper, a restoration test is presented and the effect of the magnetic coupling is widely discussed by means of some parametric analyses, performed with the software DIgSILENT PowerFactory