| Type | Effect on RMS voltage | Final Magnitude | Duration of effect on RMS voltage |
| (a): Short duration voltage variation | |||
| Instantaneous |
|
|
|
| Sag | decrease | 0.1 - 0.9 pu | 0.5 - 30 cycles |
| Swell | increase | 0.1 - 1.8 pu | 0.5 - 30 cycles |
| Momentary |
|
|
|
| Sag | decrease | 0.1 - 0.9 pu | 0.5 cycle to 1 minute |
| Swell | increase | 1.1 - 1.8 pu | 0.5 cycle to 1 minute |
| Interruption (v. short) | decrease | <0.1 pu | 0.5 cycles - 3 s |
| Temporary |
|
|
|
| Sag | decrease | 0.1 - 0.9 pu | 3 s - 1 minute |
| Swell | increase | 1.1 - 1.2 pu | 3 s - 1 minute |
| Interruption (Short) | decrease | <0.1 pu | ≤3 minutes |
| (b): Long duration voltage variation | |||
| Over Voltage | increase | 1.1 - 1.2 pu | >1 minute |
| Under Voltage | decrease | 0.8 - 0.9 pu | >1 minute |
| Interruption (Long) | decrease | 0.0 pu | >3 minute |