Grounding Transformers


Pioneer manufactures Grounding Transformers with maximum primary voltage of 72,5 kV (350 kV BIL) with or without an auxiliary/secondary winding. Units can be supplied with cover or wall mounted bushings within a full height air terminal chamber, a bus duct throat or a junction box. All units comply either with the latest CSA or ANSI standards.

What is a grounding transformer?

A grounding transformer is used to provide a path to ground for unbalanced load current and for fault currents on systems where a suitable ground is otherwise not available. Grounding transformers are normally constructed with one of the two configurations: Zig-Zag (Zn) with or without an auxiliary winding or a Wye (Ynd) with a delta connected secondary. The Zig-Zag connection is preferred as it is more cost effective and physically smaller than the Delta-Wye unit. For added safety, neutral ground resistors (NGR) are often used in conjunction with the grounding transformer to limit neutral ground fault current magnitude. The rated voltage of the NGR should be equal to the line to ground voltage of the grounding transformer. The current rating and duration should match the grounding transformer ratings. It is important to set the current rating high enough to be above the cable charging current and grounding transformer magnetizing current.

Optional Features

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