Sr-No

Subject

Type of Disturbance

Time Duration

Range

Minimum Value

Maximum Value

1

Frequency

Slight deviation

10 s

49.50 Hz

50.50 Hz

Sever deviation

47 Hz

52 Hz

2

Voltage

Average Voltage

10 min

0.85 Un

1.1 Un

Flicker

-

-

7%

Sag

Short

10 ms - 1 s

0.1 U

0.9 U

Long

1 s - 1 min

Long-Time Disturbances

>1 min

Under Voltage

Short

<3 min

0.99 U

-

Long

>3 min

Swell

Temporary short

10 ms - 1 s

1.1 U

1.5 kV

Temporary Long

1 s - 1 min

Temporary-Long Time

>1 min

Over Voltage

<10 ms

6 kV

3

Harmonics & Miscellaneous Signals

Harmonics

-

THD > 8%

-

Miscellaneous Signals

-

Including in Other Disturbance

-