Protective Characteristics of an Arrester   IEC and IEEE

The combination of the following:

1. Residual voltage for steep current impulse.
2. Residual voltage versus discharge current characteristic for lightning impulses.
NOTE 1 The lightning impulse protection level of the arrester is the maximum residual voltage for the nominal discharge current.
3. residual voltage for switching impulse.
NOTE 2 The switching impulse protection level of the arrester is the maximum residual voltage at the specified switching impulse currents.