Ground Fault Protection (GFP): Difference between revisions
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== Different type of ground fault protections == | == Different type of ground fault protections == | ||
(see | (see {{FigRef|F27}})<br> | ||
Three types of GFP are possible dependind on the measuring device installed : | Three types of GFP are possible dependind on the measuring device installed : | ||
| Line 14: | Line 14: | ||
*“Source Ground Return” SGR | *“Source Ground Return” SGR | ||
The « insulation fault current » is measured in the neutral – earth link of the LV | The « insulation fault current » is measured in the neutral – earth link of the LV transformer. The current transformer is outside the circuit-breaker. | ||
*“Zero Sequence” ZS | *“Zero Sequence” ZS | ||
The « insulation fault » is directly measured at the secondary of the current transformer using the sum of currents in live conductors. This type of GFP is only used with low fault current values. | The « insulation fault » is directly measured at the secondary of the current transformer using the sum of currents in live conductors. This type of GFP is only used with low fault current values. | ||
[[File:FigF27.jpg|500px|none]] | [[File:FigF27.jpg|500px|none]] | ||
'''''Fig. F27:'''''<i> Different types of ground fault protections</i> | '''''Fig. F27:'''''<i> Different types of ground fault protections</i> | ||
== Positioning GFP devices in the installation == | == Positioning GFP devices in the installation == | ||
{| class="wikitable | {| class="wikitable" | ||
|- | |- | ||
! Type / installation level | ! Type / installation level | ||
| Line 37: | Line 33: | ||
|- | |- | ||
| Source Ground Return (SGR) | | Source Ground Return (SGR) | ||
| {{ | | {{EmptyBlueSquare}} | ||
| | | | ||
| Used | | Used | ||
|- | |- | ||
| Residual Sensing (RS) (SGR) | | Residual Sensing (RS) (SGR) | ||
| {{ | | {{EmptyBlueSquare}} | ||
| {{ | | {{BlueSquare}} | ||
| Often used | | Often used | ||
|- | |- | ||
| Zero Sequence (SGR) | | Zero Sequence (SGR) | ||
| {{ | | {{EmptyBlueSquare}} | ||
| {{ | | {{BlueSquare}} | ||
| Rarely used | | Rarely used | ||
|} | |} | ||
Revision as of 15:14, 24 November 2016
Different type of ground fault protections
(see Fig. F27)
Three types of GFP are possible dependind on the measuring device installed :
- “Residual Sensing” RS
The “insulation fault” current is calculated using the vectorial sum of currents of current transformers secondaries. The current transformer on the neutral conductor is often outside the circuit-breaker.
- “Source Ground Return” SGR
The « insulation fault current » is measured in the neutral – earth link of the LV transformer. The current transformer is outside the circuit-breaker.
- “Zero Sequence” ZS
The « insulation fault » is directly measured at the secondary of the current transformer using the sum of currents in live conductors. This type of GFP is only used with low fault current values.
Fig. F27: Different types of ground fault protections
Positioning GFP devices in the installation
| Type / installation level | Main-distribution | Sub-distribution | Comments |
|---|---|---|---|
| Source Ground Return (SGR) | [math]\displaystyle{ \definecolor{bggrey}{RGB}{234,234,234}\pagecolor{bggrey}\definecolor{myblue}{rgb}{0.26,0.71,0.9}\color{myblue}\square }[/math] | Used | |
| Residual Sensing (RS) (SGR) | [math]\displaystyle{ \definecolor{bggrey}{RGB}{234,234,234}\pagecolor{bggrey}\definecolor{myblue}{rgb}{0.26,0.71,0.9}\color{myblue}\square }[/math] | [math]\displaystyle{ \definecolor{bggrey}{RGB}{234,234,234}\pagecolor{bggrey}\definecolor{myblue}{rgb}{0.26,0.71,0.9}\color{myblue}\blacksquare }[/math] | Often used |
| Zero Sequence (SGR) | [math]\displaystyle{ \definecolor{bggrey}{RGB}{234,234,234}\pagecolor{bggrey}\definecolor{myblue}{rgb}{0.26,0.71,0.9}\color{myblue}\square }[/math] | [math]\displaystyle{ \definecolor{bggrey}{RGB}{234,234,234}\pagecolor{bggrey}\definecolor{myblue}{rgb}{0.26,0.71,0.9}\color{myblue}\blacksquare }[/math] | Rarely used |
[math]\displaystyle{ \color{RoyalBlue}\Box }[/math] Possible
[math]\displaystyle{ \color{RoyalBlue}\blacksquare }[/math] Recommended or required
