GE Multilin
F35 Multiple Feeder Protection System
5-205
5 SETTINGS
5.7 CONTROL ELEMENTS
5
f) THERMAL OVERLOAD PROTECTION
(ANSI 49)
PATH: SETTINGS
CONTROL ELEMENTS
MONITORING ELEMENTS
THERMAL OVERLOAD PROTECTION
THERMAL
PROTECTION 1(2)
The thermal overload protection element corresponds to the IEC 255-8 standard and is used to detect thermal overload
conditions in protected power system elements. Choosing an appropriate time constant element can be used to protect dif-
ferent elements of the power system. The cold curve characteristic is applied when the previous averaged load current over
the last 5 cycles is less than 10% of the base current. If this current is greater or equal than 10% than the base current, then
the hot curve characteristic is applied.
The IEC255-8 cold curve is defined as follows:
(EQ 5.22)
The IEC255-8 hot curve is defined as follows:
(EQ 5.23)
In the above equations,
•
t
op
= time to operate
•
τ
op
= thermal protection trip time constant
•
I
= measured overload RMS current
•
I
p
= measured load RMS current before overload occurs
•
k
= IEC 255-8 k-factor applied to
I
B
, defining maximum permissible current above nominal current
•
I
B
= protected element base (nominal) current
THERMAL
PROTECTION 1
THERMAL PROTECTION 1
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
THERMAL PROTECTION 1
SOURCE: SRC1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
MESSAGE
THERMAL PROTECTION 1
BASE CURR: 0.80 pu
Range: 0.20 to 3.00 pu in steps of 0.01
MESSAGE
THERMAL PROTECTION 1
k FACTOR: 1.10
Range: 1.00 to 1.20 in steps of 0.05
MESSAGE
THERM PROT 1 TRIP
TIME CONST: 45 min.
Range: 0 to 1000 min. in steps of 1
MESSAGE
THERM PROT 1 RESET
TIME CONST: 45 min.
Range: 0 to 1000 min. in steps of 1
MESSAGE
THERM PROT 1 MINIM
RESET TIME: 20 min.
Range: 0 to 1000 min. in steps of 1
MESSAGE
THERM PROT 1 RESET:
Off
Range: FlexLogic operand
MESSAGE
THERM PROT 1 BLOCK:
Off
Range: FlexLogic operand
MESSAGE
THERMAL PROTECTION 1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
THERMAL PROTECTION 1
EVENTS: Disabled
Range: Disabled, Enabled
t
op
τ
op
I
2
I
2
kI
B
(
)
2
–
--------------------------
ln
×
=
t
op
τ
op
I
2
I
p
2
–
I
2
kI
B
(
)
2
–
--------------------------
ln
×
=
Summary of Contents for UR F35 Series
Page 10: ...x F35 Multiple Feeder Protection System GE Multilin TABLE OF CONTENTS ...
Page 366: ...5 238 F35 Multiple Feeder Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 426: ...10 12 F35 Multiple Feeder Protection System GE Multilin 10 6 DISPOSAL 10 MAINTENANCE 10 ...
Page 454: ...A 28 F35 Multiple Feeder Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 620: ...F 12 F35 Multiple Feeder Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Page 630: ...H 8 F35 Multiple Feeder Protection System GE Multilin H 3 WARRANTY APPENDIX H H ...
Page 640: ...x F35 Multiple Feeder Protection System GE Multilin INDEX ...