5-12
F-PRO 116 User Manual
D05125R01.20
𝑡 = 𝜏 × 𝑙𝑛
𝐼
2
− 𝐼
𝑃
2
𝐼
2
− (𝑘 × 𝐼
𝐵
)
2
Where,
t
= Operating time in minutes
= Thermal time constant in minutes
Ln
= Natural log
Ip
= Steady state relay current prior to overload
IB
= Basic current
I
= Effective relay current
Basic current IB is full load current of the protected feeder. Constant k is a multiplying factor
resulting in the 49 Thermal OL setting of the relay Iθ which is equal to k.IB. Thermal time constant
–
for the relay can be set based on the protecting equipment thermal withstand capability. The
effective relay current I is calculated as below:
Where:
I
= Effective relay current
IRMS
= Each phase RMS current
I2
= Negative sequence current
K
= Negative sequence weighing factor
The thermal operating time of thermal OL function is based on prior load current to the relay. If
Ip <0.02IB prior to thermal OL condition, then it is treated as cold condition, hence it adopts cold
curve. If Ip is greater than zero prior to thermal OL condition, then it is treated as hot condition,
hence it adopts hot curve.
Thermal state (
θ
) for the heating curve is calculated as below:
Thermal state (
θ
) for the cooling [or] reset curve is calculated as below:
I
q
=
2
I
2
q
. (1 - e ) . 100%
-t
q
=
. e
-t
q
F
t =
. Ln
[or]
q
q
F
Summary of Contents for F-PRO 116
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Page 12: ...1 2 F PRO 116 User Manual D05125R01 20 Figure 1 1 F PRO 116 Relay Function Line Diagram...
Page 16: ...1 6 F PRO 116 User Manual D05125R01 20 Figure 1 4 Ordering Template...
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Page 84: ...7 12 F PRO 116 User Manual D05125R01 20 Figure 7 10 Point Map...
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Page 149: ...D05125R01 20 F PRO 116 User Manual Appendix H 1 Appendix H Mechanical Drawings H 1 Front View...
Page 150: ...Appendix H 2 F PRO 116 User Manual D05125R01 20 H 2 Rear View...
Page 151: ...D05125R01 20 F PRO 116 User Manual Appendix I 1 Appendix I AC Schematic Drawing...
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Page 153: ...D05125R01 20 F PRO 116 User Manual Appendix J 1 Appendix J DC Schematic Drawing...
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Page 155: ...D05125R01 20 F PRO 116 User Manual Appendix K 1 Appendix K Connection Diagram...
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