HVDC QUIZ-3

The maximum value of the harmonic current depends on

• firing angle

• overlap angle

• DC current

• both firing angle and overlap angle

Using the Ud/Id characteristics, what happened in a HVDC transmission with the value of firing angle, if AC voltage RMS value decreases in the inverter station (All other condition remain unchanged)

a) γ increases at inverter side

b) γ decreases at inverter side

c) Alpha decreases at Rectifier side

d) Alpha Increases at Rectifier side

• a) and c)

• 
  a) and d)

• b) and c)

• b) and d)

If only 11th order harmonic is required to be eliminated then which of the following filter is preferred?

• Tuned Filter

• Damped Filter

The lowest current harmonic produced in 12-pulse converters is

• 23

• 25

• 11

• 13

Filters used in 12-pulse converters usually on the AC side are

• 11th, 13th and high-pass

• 5th, 7th and high-pass

• 6th, 12th and high-pass

• Only high-pass filter

Converter transformer act as a source of generation of harmonics because of

• Magnetostiction

• nonlinear nature of B–H curve of iron core

• magnetising current

• none of the above

Increase in pulse number has the effect of

• increasing harmonics

• decreasing the harmonic number

• increasing the lowest harmonic number

• no effect

The maximum value of the harmonic current depends on____.

• firing angle

• overlap angle

• both firing angle and overlap angle

• DC current 

If pulse number is = p and k is an integer, the voltage harmonic generated on the AC side is_____.

• pk

• 2pk

• pk ± 1

• 2pk ± 1

Which harmonics are easy to eliminate from the system?

• Lower

• Higher

• Odd

• even