Zig Zag Transformer

dear,

NO. There is not a difference. This is normally used in protection systems, to reduce ground fault levels in 3 phase 3 wire systems.

Dear,

There is not at all the difference.

Zig Zag trasnformers create the neutral to sense the grounding faults in 3 phase 3 wire systems. This may be very usefull in over head transmission lines protection. or for protection of Delta connected transformers. ( during the phase to ground fault, zig zag tr. secondary senses the un balanced neutral current that goes to earth fault relay, for tripping a breaker.

It depends on application usage.

A zig Zag Grounding Transformer is often used as a ground source on the delta side of a transformer or as ground path for an unground "Y". A few of the most benefits of a Zig Zag grounding transformer including.
1- Allow the connection of neutral to phase loads.
2- Hinders the probability of transient over voltages in the scenario of re striking grounding faults.
3- Allows ground fault currents a path during line to ground faults.
4- Maintains near ground potential or system neutral with a low impendence path to ground.

while a zig zag transformer is a three phase transformer and also a special purpose transformer. Its applications are:

1- As an auto transformer
2- As an earth reference point for ungrounded electrical systems
3- As a control for harmonic currents
4- As a vector phase shifter in combination with delta and Y connection
5- As a voltage transformer and isolation in two winding applications
6- In special applications where conventianal transformers are no as effective.

When considering a Zig Zag transformer. It is important the following points consideration.
1- System impendence per phase
2- magnitude of neutral current
3- Line to line voltage of the system
4- How long the neutral current will flow.

I appreciate the responses so far. I am wondering, as I look upon the drawings posted in http://www.electrical-contractor.net/forums/ubbthreads.php/topics/148726/Grounding_Transformers_Zig_Zag.html

about the zig-zag wiring. It seems to be breaking the "legs" or phases of a wye-connected transformer into opposite-flowing current. what is the purpose? Is it in order to create an auto-transformer? How does it affect the voltage?

It seems to be like the windings in, e.g. a 230/460V option motor. Does it necessarily use six separate transformers, or is there a single transformer able to be wired this way?