Fig. 5

The residual and adaptive threshold following the attack inject to the region 3: (a) The residual of the rotor angle in region \(\left( 2\right)\) without abnormal signal, (b) The residual of the rotor angle in region \(\left( 3\right)\) with the abnormal signal, (c) The residual of the rotor angle 1 in region \(\left( 1,2\right)\) without abnormal signal, (d) The residual of the rotor angle 2 in region \(\left( 1,2\right)\) without abnormal signal, (e) The residual of the rotor angle 1 in region \(\left( 1,3\right)\) with the abnormal signal, (f) The residual of the rotor angle 2 in region \(\left( 1,3\right)\) with the abnormal signal.