Functions
2.17 Flexible Protection Functions
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
284
2.17 Flexible Protection Functions
The flexible protection function is a general function applicable for a variety of protection principles depending
on its parameter settings. The user can create up to 20 flexible protection functions. Each function can be used
either as an autonomous protection function, as an additional protective element of an existing protection func-
tion or as a universal logic, e.g. for monitoring tasks.
2.17.1 Functional Description
General
The function is a combination of a standard protection logic and a characteristic (measured quantity or derived
quantity) that is adjustable via parameters. The characteristics listed in table 2-20 and the derived protection
functions are available.
Table 2-20 Possible Protection Functions
Section 2.18 gives an application example of the function „reverse power protection“.
The maximum 20 configurable protection functions operate independently of each other. The following descrip-
tion concerns one function; it can be applied accordingly to all other flexible functions. The logic diagram 2-106
illustrates the description.
Characteristic
Group
Characteristic / Measured Quantity Protective Function ANSI No. Operating Mode
3-phase 1-phase
Current I RMS value of fundamental
component
Time overcurrent protection 50, 50G X X
I
rms
True RMS (r.m.s. value) Time overcurrent protection
Overload protection
50, 50G X X
3I
0
Zero sequence system Time overcurrent protection,
ground
50N X
I1 Positive sequence component X
I2 Negative sequence compo-
nent
Negative sequence protection 46 X
I2/I1 Negative/positive sequence
component ratio
X
Frequency f Frequency Frequency protection 81U/O without phase
reference
df/dt Frequency change Frequency change protection 81R
Voltage V RMS value of fundamental
component
Voltage protection
Displacement voltage
27, 59, 59G X X
V
rms
True RMS (r.m.s. value) Voltage protection
Displacement voltage
27, 59, 59G X X
3V
0
Zero-sequence system Displacement voltage 59N X
V
1
Positive sequence component Voltage protection 27, 59 X
V
2
Negative sequence compo-
nent
Voltage asymmetry 47 X
Power P Active power Reverse power protection
Power protection
32R, 32, 37 X X
Q Reactive power Power protection 32 X X
cos ϕ Power factor Power factor 55 X X
Binary input – Binary input External trip commands without phase refer-
ence
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