What are advantages and disadvantages each for delta and Y power system?

Question

What are the advantages and disadvantages each for a delta power system and a grounded Y power system? I am referring this as a high voltage distribution system (2.2kv to 69kv).

Answer 1

As RHSAUNDERS says. A purely delta configuration can give out of balance voltages between phases.... this can cause havoc with equipment and consurmers connected to the system.
A "Purely" delta configuration means that both ends of the transmission line are connected to a delta transformer winding.
The normal transmission configuration is to have the line connected to a WYE or Star transformer winding at the commencement of the line with the Star point grounded either through a resistance/choke to limit the ground fault current. This allows for any ground faults to be sensed at the start of the line and to trip the circuit breaker to interrupt power feeding into the fault.

Answer 2

A delta system requires one fewer conductor, but unbalanced currents in the different legs can cause havoc if care is not taken. Typical practice is to use a delta configuration at each end of the transmission line; the other side of the transformers may be connected Y-style to better handle unbalanced currents.