Siemens SIPROTEC 7SD610 User Manual

Functions
2.14 Thermal Overload Protection
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
198
Calculating the overtemperature
The thermal replica is calculated individually for each phase. Address 4206 CALC. METHOD decides whether
the highest of the three calculated temperatures (Θ max) or their arithmetic average (Average Θ) or the tem-
perature calculated from the phase with maximum current (Θ from Imax) should be decisive for the thermal
alarm and tripping stage.
Since overload is usually a symmetrical process, this setting is of minor importance. If asymmetrical overloads
are to be expected, however, these options lead to different results.
Averaging should only be used if a rapid thermal equilibrium is possible in the protected object, e.g. with belted
cables. If the three phases are, however, more or less thermally isolated (e.g. single conductor cables or over-
head lines), one of the maximum settings should be chosen at any rate.
2.14.3 Settings
The table indicates region-specific presettings. Column C (configuration) indicates the corresponding second-
ary nominal current of the current transformer.
2.14.4 Information List
Addr. Parameter C Setting Options Default Setting Comments
4201 Ther. OVERLOAD OFF
ON
Alarm Only
OFF Thermal overload protec-
tion
4202 K-FACTOR 0.10 .. 4.00 1.10 K-Factor
4203 TIME CONSTANT 1.0 .. 999.9 min 100.0 min Time Constant
4204 Θ ALARM 50 .. 100 % 90 % Thermal Alarm Stage
4205 I ALARM 1A 0.10 .. 4.00 A 1.00 A Current Overload Alarm
Setpoint
5A 0.50 .. 20.00 A 5.00 A
4206 CALC. METHOD Θ max
Average Θ
Θ from Imax
Θ max Method of Acquiring Tem-
perature
No. Information Type of In-
formation
Comments
1503 >BLK ThOverload SP >BLOCK Thermal Overload Protection
1511 Th.Overload OFF OUT Thermal Overload Protection OFF
1512 Th.Overload BLK OUT Thermal Overload Protection BLOCKED
1513 Th.O/L ACTIVE OUT Thermal Overload Protection ACTIVE
1515 Th.O/L I Alarm OUT Th. Overload: Current Alarm (I alarm)
1516 Th.O/L Θ Alarm OUT Th. Overload Alarm: Near Thermal Trip
1517 Th.O/L Pickup OUT Th. Overload Pickup before trip
1521 Th.O/L TRIP OUT Th. Overload TRIP command

Siemens SIPROTEC 7SD610 Specifications

General

Brand	Siemens
Model	SIPROTEC 7SD610
Category	Relays
Language	English