Siemens 6MD85, Manual

Page: 1088 / 1256

[fo_ibs_ccm_cur_thresh, 1, en_US]
Thus. the secondary infeed current results as follows with a phase angle to the voltage ∠I
act-sec
= -90°:
[fo_ibs_ccm_cur_inp, 1, en_US]
The calculation from the values of the Table 10-2 with a pickup value of 50 % results in the following for the
transformer T
1
:
[fo_ibs_ccm_cur_inp_value, 1, en_US]
With I
sec
> 0.76 mA and ∠
act-sec
= -90°
Primary Tests
If secondary test equipment is connected to the device, remove it or switch the test switch to the operating
position.
•
To be able to control the on-load tap changer manually, switch the voltage controller to the
Manual
operating mode.
i
i
NOTE
Be aware that a trip occurs in case of incorrect connections.
Checking the Polarity of the Voltage Transformer and Current Transformer
The correct connection of the current and voltage transformers is tested using the load current via the feeder
to be controlled. For this, you must switch on the line or the protected object. A load current of at least 0.1 ⋅
I
rated
must flow through the line or the protected object. The load current should be ohmic to ohmic inductive.
The direction of the load current must be known. If there is a doubt, open meshed or ring systems.
The line or the protected object remains switched on for the duration of the measurements. You can derive
the direction directly from the operational measured values.
•
Make sure in DIGSI 5 or on the device with the following path that the power measured values corre-
spond to the power direction:
Main menu →
Measured Values
→
Voltage cont.2w
→
Power values
.
If active power flows in the line or the protected object, the power direction for P must be positive. If inductive
reactive power flows in the line or the protected object, the power direction for Q must be positive. If the
power measured values have a different sign than expected, then the power flow is opposite the current-
direction definition. This can be the case, for example, at the opposite end of the low-voltage side of a trans-
former. The current-transformer neutral point then points in the direction of the protected object (for
example, transformer). In this case, you must connect the Measuring point I-3ph in an inverted way to the
function group Voltage controller in the function-group assignment (see chapter
Interface Between Function
Group and Measuring Point, Page 36 ).
10.10.2
Functional Tests
10.10 Commissioning Hints for Voltage Control
1088 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017