The converters are stating using high power ___ connected in __ to give the required voltage ratings.

• transistors, parallel
• thyristors, parallel
• thyristors, series
• transistors, series

The number of conductors in DC transmission line is

• 2
• 3
• 1
• 4

The bridge circuit of converter unit is called _

• Graetz unit
• Valve bridge
• pole bus
• smoothing bus

The total number of valves in each unit of the converter valve is

• 14
• 12
• 10
• 13

The AC and DC harmonics are generated in __

• substations
• HVAC Converters
• HVDC Converters
• all the options are correct

Advantages of HVDC transmission over AC system is / are

• Reversal of power can be controlled by firing angle
• Very good dynamic behavior
• They can link two AC system operating unsynchronized
• All the options are correct

Which of the following is Multi terminal HVDC system?

• Monopolar
• Bipolar
• Homopolar
• Both Monopolar and Bipolar

The high voltage drop occurs across the AC terminal lines when their end terminals voltage are__

• low
• equal
• different
• high

In HVDC converter station equipment using thyristors it is necessary to use a large number of thyristors in series because

• Current ratings of thyristors are low
• Voltage ratings of thyristors are low.
• Thyristors always fail to an internal open circuit.
• None of the options are correct

By which of the following method string efficiency can be improved?

• Using a guard ring
• Grading the insulator
• Using long cross arm
• all the options are correct