Siemens 7SJ85 - Application and Setting Notes

Selection and Setting of the Rated Current
With the parameter Rated-current selection, you define whether this function uses the rated current
of the whole capacitor bank or the individual rated current of the protected object (for example, reactor or
resistor branch within the capacitor-bank installation) as the reference value. This function uses the reference
value for current normalization in thermal-replica calculation, for percentage-measured values, and for thresh-
olds set in percentages.
If you select the individual rated current of the protected object as the reference value, set the individual rated
current in the FB General of the Overload RLC function.
Functional Measured Values
Measured Values Description Primary Secondary % Referenced to
(_:13501:301) Iph 3-phase currents of the meas-
uring point
A A Parameter Capacitor
reference curr. or RLC
rated current depending
on the setting of parameter
Rated-current selec-
tion
(_:601:304) Time
until close
Time until close release s s s
(_:601:305) Time
until trip
Estimated time until tripping s s s
(_:601:306) Over-
load phase A
Thermal measured values of
phases
% % Trip temperature
(_:601:307) Over-
load phase B
(_:601:308) Over-
load phase C
(_:601:309) Over-
load maximum
Thermal measured values of
overload protection
% % Trip temperature
(_:601:310)
Equival. current
phs A
Current measured value as
base for overload measured
value
A A Parameter Capacitor
reference curr. or RLC
rated current depending
on the setting of parameter
Rated-current selec-
tion
(_:601:311)
Equival. current
phs B
(_:601:312)
Equival. current
phs C
(_:601:313)
Equival. current
max.
Maximum current measured
value as base for overload
value
A A Parameter Capacitor
reference curr. or RLC
rated current depending
on the setting of parameter
Rated-current selec-
tion
Application and Setting Notes
Parameter: MP selection
•
Default setting (_:13501:81) MP selection = no MP configured
With the MP selection parameter, you can select a measuring point that is connected to the I 3ph RLC
interface in the Capacitor bank function group.
7.3.4
Capacitor Bank Protection
7.3 Thermal Overload Protection for Capacitor Banks
974 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017