# Grounding transformer

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Grounding_transformer
> Markdown URL: https://mediated.wiki/source/Grounding_transformer.md
> Source: https://en.wikipedia.org/wiki/Grounding_transformer
> Source revision: 1264092660
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{Short description|Power engineering device}}
thumb|A grounding transformer
A '''grounding transformer''' or '''earthing transformer''' is a type of auxiliary [transformer](/source/transformer) used in [three-phase electric power](/source/three-phase_electric_power) systems to provide a ground path to either an ungrounded wye or a delta-connected system.<ref>{{cite web |url=http://www.swedishneutral.se/download/Swedish%20Neutral%20Grounding%20Transformer%20Technical%20Specification%20English.pdf |title=Grounding Transformer |website=Swedish Neutral}}</ref><ref name=":0">{{cite web |url=http://www.ecmweb.com/bonding-amp-grounding/grounding-transformers |title=Grounding Transformers |last=Dickinson |first=Mike |date=August 19, 2011 |website=Pacific Crest Transformers |access-date=September 4, 2017}}</ref> Grounding transformers are part of an [earthing system](/source/earthing_system) of the network. They let [three-phase](/source/three-phase) ([delta connected](/source/delta-wye_transformer)) systems accommodate phase-to-neutral loads by providing a return path for current to a neutral.

Grounding transformers are typically used to:
* Provide a relatively low-impedance path to ground, thereby maintaining the system neutral at or near ground potential.<ref>{{cite web |url=https://pact.in/blog/2021/08/what-is-a-floating-neutral |title=Floating Neutral Transformer |website=Neutral Transformers|date=14 August 2021 }}</ref>
* Limit the magnitude of transient over voltages when restriking ground faults occur.
* Provide a source of ground fault current during line-to-ground faults.
* Permit the connection of phase-to-neutral loads when desired.<ref name=":0"/>

thumb|Earthing transformer with a zig-zag
Grounding transformers most commonly incorporate a single winding transformer with a [zigzag](/source/zigzag_transformer) winding configuration, but may also be created with a (rare case) [delta-wye transformer](/source/delta-wye_transformer).<ref name=":0"/><ref>{{cite web |url=https://www.pacificcresttrans.com/grounding-transformer-faqs/ |title=Grounding Transformer FAQs |date=November 8, 2013 |website=Pacific Crest Transformers |access-date=September 4, 2017 |archive-date=August 13, 2018 |archive-url=https://web.archive.org/web/20180813182725/http://www.pacificcresttrans.com/grounding-transformer-faqs/ |url-status=dead }}</ref> Neutral grounding transformers are very common on generators in power plants and wind farms.<ref name=":0"/> Neutral grounding transformers are sometimes applied on high-voltage (sub-transmission) systems, such as at 33 kV, where the circuit would otherwise not have a ground; for example, if a system is fed by a delta-connected transformer. The grounding point of the transformer may be connected through a resistor or arc suppression coil to limit the fault current on the system in the event of a line-to-ground fault. <ref>Martin Heathcote (ed.), ''J & P Transformer Book'', Newnes, 2011 {{ISBN|0080551785}}pp. 421-422 </ref>

==References==
{{Reflist}}

{{Electric transformers}}

Category:Electric transformers
Category:Power engineering

{{Electric-power-stub}}

---
Adapted from the Wikipedia article [Grounding transformer](https://en.wikipedia.org/wiki/Grounding_transformer) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Grounding_transformer?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.