Instruction manual
–
AQ G3x7 Generator protection IED
171 (211
)
Binary status signal
Explanation
VTS_Blk_GrO_
Output status defined by the user to disable the voltage
transformer supervision function.
Table 3-76: The binary input signal of the voltage transformer supervision function
Binary output signals
Signal title
Explanation
VTS_Fail_GrI
VT Failure
Failure status signal of the VTS function
Table 3-77: The binary output signal of the voltage transformer supervision function
Table 3-78Setting parameters of the voltage transformer supervision function
Parameter
Setting value, range
and step
Description
Operation
Off
Neg. Sequence
Zero sequence
Special
Operating mode selection for the function. Operation can be either
disabled
“
Off
”
or enabled with criterions
“
Neg.Sequence
”
,
“
Zero
sequence
”
or
“
Special
”
. Default setting is enabled with negative
sequence criterion.
Start URes
5
…
50 % by step of 1
%
Residual voltage setting limit. Default setting is 30 %.
Start IRes
10
…
50 % by step of
1 %
Residual current setting limit. Default setting is 10 %.
Start UNeg
5
…
50 % by step of 1
%
Negative sequence voltage setting limit. Default setting is 10 %.
Start INeg
10
…
50 % by step of
1 %
Negative sequence current setting limit. Default setting is 10 %.
3.3.5
C
URRENT TRANSFORMER SUPERVISION
(CTS)
The current transformer supervision function can be applied to detect unexpected
asymmetry in current measurement.
The function block selects maximum and minimum phase currents (fundamental Fourier
components). If the difference between them is above the setting limit, the function
generates a start signal. For function to be operational the highest measured phase current
shall be above 10 % of the rated current and below 150% of the rated current.
The function can be disabled by parameter setting, and by an input signal programmed by
the user.
The failure signal is generated after the defined time delay.