Functions
2.1 General
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
45
2.1.6
Power System Data 2
2.1.6.1
Description
The general protection data (
P.System Data 2
) includes settings associated with all functions rather than a
specific protection or monitoring function. In contrast to the
P.System Data 1
as discussed before, they can
be changed over with the setting groups.
Applications
If the primary reference current of the protected object is set, the device is able to calculate and output the per-
centage operational measured values.
For protection of motors the motor starting detection represents an important feature. Exceeding a configured
current value serves as a criterion.
2.1.6.2
Setting Notes
Definition of Nominal Rated Values
At address
1102
FullScaleCurr.
, the primary reference current (phase) of the protected equipment is
entered (e.g. motors). If this reference variable matches the primary value of the current transformer, it is equiv-
alent to the setting at Address
204
(Section 2.1.3.2). They are generally used to show values as a percentage
of full scale.
Recognition of Running Condition (Only for Motors)
When the configured current value at Address
1107
I MOTOR START
is exceeded, this will be interpreted as
motor starting. This parameter is used by the start-up time monitoring and overload protection functions.
For this setting the following should be considered:
• A setting must be selected that is lower than the actual motor start-up current under all load and voltage
conditions.
• During motor start-up the thermal replica of the overload protection is "frozen", i.e. kept at a constant level.
This threshold should not be set unnecessarily low since it limits the operating range of the overload protec-
tion for high currents during operation.