> However... AC is still the standard. And changing power standards is awfully slow, because power cables in the ground can easily have a lifespan of 50+ years, and there is a chicken and egg problem involved with deploying a new standard.
The lines can theoretically stay the same, at least in the distribution network - you'd "only" need to exchange the equipment like transformers and switches.
DC has some pretty challenging aspects in implementation, and that not just on the large grid scale:
- changing voltages requires active semiconductors instead of a (relatively) dumb transformer. This has been lessened by technological advances, but it's still more expensive.
- switching DC loads on and off is harder because the voltage never crosses the zero threshold - this is also the reason why relays and circuit breakers are always rated for way lower currents in DC than in AC, and usually have lower cycle ratings as well as there will be an arc that continuously burns.
- the same is also true for ground faults, say a tree branch: the arc isn't "automatically" extinguished once the voltage drops (which happens every 1/50 second)
- it's more difficult to have an actual grid, most current implementations are point-to-point only
- DC introduces the potential for very weird "stray currents" and resulting electrochemical corrosion
- unlike with multi-phase AC, the magnetic forces in a cable that are generated by current flow don't cancel each other out, so that needs to be taken into consideration to verify if cables are suited for DC transmission
The lines can theoretically stay the same, at least in the distribution network - you'd "only" need to exchange the equipment like transformers and switches.
DC has some pretty challenging aspects in implementation, and that not just on the large grid scale:
- changing voltages requires active semiconductors instead of a (relatively) dumb transformer. This has been lessened by technological advances, but it's still more expensive.
- switching DC loads on and off is harder because the voltage never crosses the zero threshold - this is also the reason why relays and circuit breakers are always rated for way lower currents in DC than in AC, and usually have lower cycle ratings as well as there will be an arc that continuously burns.
- the same is also true for ground faults, say a tree branch: the arc isn't "automatically" extinguished once the voltage drops (which happens every 1/50 second)
- it's more difficult to have an actual grid, most current implementations are point-to-point only
- DC introduces the potential for very weird "stray currents" and resulting electrochemical corrosion
- unlike with multi-phase AC, the magnetic forces in a cable that are generated by current flow don't cancel each other out, so that needs to be taken into consideration to verify if cables are suited for DC transmission