Zig-Zag Transformer
A special transformer with interconnected windings creating a neutral for grounding in three-phase systems.
A zig-zag has each limb carrying two winding halves from different phases in opposing polarity, creating neutral with low zero-sequence impedance and high positive/negative-sequence impedance.
Under balanced conditions, voltages cancel. During ground faults, provides low-impedance path for zero-sequence.
Applications: artificial neutral for delta/ungrounded systems, fault current limiting (with resistors), harmonic filtering (3rd harmonic path), phase balancing. Rated by neutral current and fault current rather than kVA.
QDTB designs zig-zag grounding transformers optimized for each project. See grounding guide for design guidance.
Related Products
Related Terms
Grounding Transformer
A transformer providing a neutral point for grounding in ungrounded or delta-connected systems.
Zero Sequence Current
Current components equal in all three phases flowing through neutral/ground during unbalanced or fault conditions.
Neutral Point
The common connection point of a star (wye) winding where the three-phase voltage vector sum equals zero.
Reactor
An inductive device in power systems to limit current, absorb reactive power, or filter harmonics.
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