Let's take a look at their comparison facts.. and find out the better one among them.....
|
Topic
|
HVDC
|
HVAC
|
|
Investment cost
|
lesser
|
Higher
|
|
Conductor Nos.
|
2/Dc circuit
|
3conductor/3
phase
|
|
Supporting tower
|
smaller
|
Larger
|
|
Terminal converter cost
|
Very High
|
Not required
|
|
Skin losses
|
Absent
|
present
|
|
Controllability
|
HVDC offers
greater controllability due to lack of inductance, power can be controlled
|
Lesser than
HVDC,power can’t be controlled
|
|
Interference with nearby communication lines
|
Chances
are lower
|
Chances
are higher, due to strong magnetic field.
|
|
Short circuit current rating
|
Receiving Current
in HVDC is low
|
Receiving Current
in HVAC is Higher, Circuit breaker needed of higher rating to provide safety
|
|
Asyschronous Interconnection
|
Possible
|
Impossible
due to various range of frequency and it’s fluctuations
|
|
Voltage Regulation
|
Higher than
HVAC
|
Lower Than
HVDC
|
|
For transmission
|
HVDC
is the best suitable
|
HVAC
is not the best choice, it has higher losses
|
|
For Distribution
|
HVDC , not
suitable
|
HVAC, best
suitable
|
|
Step up/down
|
Not
possible, Transformer doesn’t work in DC
|
Possible
through the usage of X-former
|
|
Frequency Fluctuation
|
No chance
|
Bigger chance,
occurs regularly
|
|
Stability in system
|
Greater
stability
|
Lesser
than HVDC
|
|
Line loss comparison
|
33% lesser
than ac line
|
33% higher
than DC line
|
|
Power factor
|
Always
unity, as resistive
|
0.945
lagging, compensation needed.
|
|
Insulators needed
|
Then, 2/3 of
AC line
|
If 1
|
|
Power carrying capacity in same tower
|
1440MVA
@380KV DC, 300% higher than AC line
|
480MVA
@ 220KV AC
|
|
Economical and Environmental Advantage
|
higher
|
lower
|
|
Directionality of link
|
Bi-polar
|
Uni-polar
|
 |
| same tower, different power carrying capacity ####So you have found out the best system among them |
