Which one is best: HVAC vs HVDC

The world has progressed so much and HVAC and HVDC are the application of the science.

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