Functions
2.14 Differential Protection and Its Protected Objects
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
112
2.14.1.2 Setting Notes
General
Differential protection is only effective and available if the type of protected object for this function was set
during protective function configuration (Section 2.4, address 120, DIFF. PROT. = Generator/Motor or 3
phase transf.). Only the relevant parameters for that object are presented, all others are hidden. If the func-
tion is not required Disabled is set. The address 2001 DIFF. PROT. serves to enable the function ON and
OFF or to block only the trip command (Block relay).
Note
When the device is delivered, the differential protection function is switched OFF. The reason is that the pro-
tection must not be in operation unless at least the connection group (of a transformer) and the matching factors
have been set beforehand. Without these settings the device may react unpredictably (e.g. tripping)!
The primary rated current I
N CTprim
of the used CTs should normally be higher than the rated current I
N, Obj.
of
the object to be protected. However, at least the following condition should be observed with regard to the upper
limit of the linear zone of the 7UM62, which is 20 · I
N
:
I
N CTprim
> 0.75 · I
N, Obj.
Additional Settings
Note
Additional parameter settings are given in separate subsections for the respective protected objects.
2.14.1.3 Settings
Addresses which have an appended "A" can only be changed with DIGSI, under Additional Settings.
Addr. Parameter Setting Options Default Setting Comments
2001 DIFF. PROT. OFF
ON
Block relay
OFF Differential Protection
2005 INC.CHAR.START OFF
ON
OFF Increase of Trip Char. During Start
2006 INRUSH 2.HARM. OFF
ON
ON Inrush with 2. Harmonic Restraint
2007 RESTR. n.HARM. OFF
3. Harmonic
5. Harmonic
OFF n-th Harmonic Restraint
2021 I-DIFF> 0.05 .. 2.00 I/InO 0.20 I/InO Pickup Value of Differential Curr.
2026A T I-DIFF> 0.00 .. 60.00 sec; ∞ 0.00 sec T I-DIFF> Time Delay
2031 I-DIFF>> 0.5 .. 12.0 I/InO; ∞ 7.5 I/InO Pickup Value of High Set Trip
2036A T I-DIFF>> 0.00 .. 60.00 sec; ∞ 0.00 sec T I-DIFF>> Time Delay
2041A SLOPE 1 0.10 .. 0.50 0.25 Slope 1 of Tripping Characteristic
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