Zero Sequence Current
Current components equal in all three phases flowing through neutral/ground during unbalanced or fault conditions.
Zero-sequence current is a symmetrical component—equal magnitude and phase in all three phases, flowing through neutral or ground. Appears during ground faults or unbalanced loading.
In star with grounded neutral: flows through lines, returns via neutral. In delta: circulates internally, cannot flow externally. Transformer ability depends on configuration and core design.
Yyn0 three-limb: limited (flux through air/tank). YNd/Dyn: delta provides path. Analysis essential for grounding and protection.
QDTB provides zero-sequence data for all products. Zig-zag transformers specifically designed for zero-sequence handling.
Related Terms
Unbalanced Load
Unequal three-phase loads causing unequal currents, neutral current, and zero-sequence effects.
Neutral Point
The common connection point of a star (wye) winding where the three-phase voltage vector sum equals zero.
Grounding Transformer
A transformer providing a neutral point for grounding in ungrounded or delta-connected systems.
Zig-Zag Transformer
A special transformer with interconnected windings creating a neutral for grounding in three-phase systems.
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