09-02-2012, 02:15 PM
BASIC HVDC AND CONVERTER OPERATION
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Why HVDC rather than HVAC?
Long distances make HVDC cheaper
Improved page link stability
Fault isolation
Asynchronous link
Inverter operation ( = 140º)
Firing is delayed so much that the entire area enclosed between the voltage waveform and the zero line is of opposite polarity.
The equation written in terms of is still correct:
Vd=Vdio -0.766-Id. Xc+Er
2
Vd=-Vdio x 0.8609
However this is usually written in terms of as follows
Vd=-Vdio(cos-Id.(Xc-Er))
2
