Introduction to Transients

In electrical engineering, spikes are fast short duration transients in the form of Voltage , Current or transferred energy.

• True

• False

Transients are generally referred as

• Phenomena with duration of less than one cycle (of power frequency 50 Hz)

• Phenomena which occurs during transition from one steady state to another steady state

• Both (a) and (b)

• Long time faults

Continuous surges are ranges from

• 250 V to 1000 V

• Upto 3000 V

• 250 V to 3000 V

• None of the above

Momentary surges are ranges from

• 250 V to 1000 V

• Above 3000 V

• 250 V to 3000 V

• None of the above

Capacitor switching is the most common switching events on utility side and it creates transients with oscillatory type of waveform

• True

• False

Magnetising inrush current is the phenomena that occurs in a transformer

• Arises due to short circuit

• Occurs due to Hysteresis loss

• During energisation time period

• Full load rated current

Wave propagation phenomena related to

• Disturbances due to electromagnetic action

• Change in mechanical conditions

• Electro - mechanical phenomena

• Transients due to external atmospheric conditions

Temporary transient over voltage is characterized by

• Standard short duration (1 min) power frequency wave shapes

• Time duration of 20 - 5000 micro seconds

• 0.1 - 20 micro seconds

• All the above

Sow front over voltages are generally caused by

• Lightning surges

• Transformer magnetizing inrush current

• Switching operations

• None of the above

Fast front over voltages are generally caused by

• Lightning surges

• Transformer magnetizing inrush current

• Switching operations

• All the above