Rev.01
44/151
Thermal image is calculated based on next equation:
θ
= 100 x (I/It)
2
x (1
–
e-t/
ζ
) +
θ’0 x e
-t/
ζ
where:
I, maximum three phase fundamental current
It, adjusted tap current
ζ
, thermal constant
θ’0, initial thermal status
Tripping time is determined by next equation:
t = ζ x ln {
[(I/It)
2
–
(θ’0 / 100) ] / [(I/It)
2
- 1] }
Tripping time accuracy is the 5% over the theorical time.
The algorithm uses the maximum current of the three phase currents. If the maximum current is higher
than the adjusted tap, heating thermal constant is applied. If maximum current is lower than the adjusted
tap, cooling thermal constant is applied.
Overload function trips when thermal image reaches the value of 100%. This value is got when the flow
current is equal to the adjusted tap for the thermal image.
A configurable level is established in order to generate an alarm. If a trip happens, the overload function
is reset when thermal image is below to the adjusted alarm level.
4.10.1 Thermal image measurement evolution graphic
On next graphic, thermal image measurement evolution can be observed depending on applied current:
With the thermal image protection adjusted with a tap of 1.1 times the nominal current and an alarm
level of 75%.
Zone 1
: The machine is deenergized for a long time. Thermal image is 0%.
Th %
t
100%
1
2
3
4
75%
alarm
trip
Summary of Contents for SIL-G
Page 1: ...USER S MANUAL USER S MANUAL SIL G Feeder Relay...
Page 8: ...www fanox com Rev 01 8 151 2 3 Connection diagrams 2 3 1 Analog current connections...
Page 10: ...www fanox com Rev 01 10 151 3 VT configuration phase neutral...
Page 11: ...www fanox com Rev 01 11 151 3 VT configuration phase neutral residual voltage...
Page 12: ...www fanox com Rev 01 12 151 3VT configuration phase phase residual voltage...
Page 13: ...www fanox com Rev 01 13 151 2VT configuration phase phase residual voltage...
Page 14: ...www fanox com Rev 01 14 151 3 VT configuration phase neutral phase B line voltage...
Page 27: ...www fanox com Rev 01 27 151 Dimensions 175x175x150 3 3 Functional diagram...
Page 28: ...www fanox com Rev 01 28 151...
Page 69: ...www fanox com Rev 01 69 151 General trip...
Page 88: ...www fanox com Rev 01 88 151...
Page 89: ...www fanox com Rev 01 89 151...
Page 90: ...www fanox com Rev 01 90 151...
Page 95: ...www fanox com Rev 01 95 151 Time Minutes Seconds Milliseconds...
Page 150: ...www fanox com Rev 01 150 151 NOTES...
Page 151: ...www fanox com Rev 01 151 151...
