The
No load
No load signal is activated when the current dips below the "No load current" limit (= 0.2 x I
n
)" for
longer than ten milliseconds. If the current increases from this situation up to the "Heavy overloading"
limit (> 1.3 x
I
n
), the
H
HV inrush de
V inrush dettection
ection and LLV inrush de
V inrush dettection
ection signals are activated. If the measured
current is between the "No load current" limit and the "Nominal current" limit, the
LLoad normal
oad normal signal is
activated. If the measured current is between the "Nominal" and the "Heavy overloading" currents, the
Ov
Overloading
erloading signal is activated.
These signals can be used for multiple purposes: information, transformer-related logics, and
monitoring. A constant, long-lasting heavy overloading can cause oil ageing in the transformer, and
thus more frequent maintenance is recommended to prevent possible problems in the transformer.
Settings and signals
The settings of the transformer status monitoring function are mostly shared with other
transformer protection functions in the transformer module of the device. The following table shows
these other functions that also use these settings.
Table. 5.3.16 - 141. Settings of the transformer status monitoring function and how they are shared by other protection functions.
Name
Range
Step
Default
Functions
Description
Transformer
nominal
0.1...500.0MVA 0.1MVA 1.0MVA All
The nominal MVA of the transformer. This
value is used to calculate the nominal
currents onf both the HV and the LV side.
HV side
nominal
voltage
0.1…500.0kV
0.1kV
110.0kV All
The HV side nominal voltage of the
transformer. This value is used to calculate
the nominal currents of the HV side.
LV side
nominal
voltage
0.1…500.0kV
0.1kV
110.0kV All
The LV side nominal voltage of the
transformer. This value is used to calculate
the nominal currents of the LV side.
Transformer
Zk%
0.01…25.00%
0.01%
3.00%
Info
The transformer's short-circuit impedance in
percentages. Used for calculating short-
circuit current.
Transformer
nom. freq.
10…75Hz
1Hz
50Hz
Info
The transformer's nominal frequency. Used
for calculating the transformer's nominal
short-circuit inductance.
Transf. vect.
group
0: Manual set
1: Yy0
2: Yyn0
3: YNy0
4: YNyn0
5: Yy6
6: Yyn6
7: YNy6
8: YNyn6
9: Yd1
10: YNd1
11: Yd7
12: YNd7
13: Yd11
14: YNd11
15: Yd5
16: YNd5
17: Dy1
18: Dyn1
19: Dy7
20: Dyn7
21: Dy11
22: Dyn11
23: Dy5
24: Dyn5
25: Dd0
26: Dd6
-
1: Yy0
- transformer status
monitoring
- transformer
differential
The selection of the transformer's vector
group. The selection values (1–26) are
predefined so that the scaling and vector
matching are applied in the relay
automatically when the correct vector group
is selected.
The predefinitions assume that the HV side is
connected to the CT1 module and that the LV
side is connected to the CT2 module.
If the protected transformer vector group is
not found in the predefined list, it can be
manually set by selecting the option "0:
Manual set".
A
AQ
Q-T215
-T215
Instruction manual
Version: 2.04
206
