Siemens 6MD85 Manual page 1089

Checking the Tap Direction and the Set Bandwidth
•
Set the bandwidth according to the formula in chapter
The tap direction and the set bandwidth are checked with the following functional test.
With the correct tap direction, there will be a voltage increase when changing to a higher tap or a voltage
reduction when changing to a lower tap.
•
First switch the voltage controller to the Manual operating mode.
•
Switch the tap changer to a higher or lower tap on the on-site operating panel or in the DIGSI Online-
Editor until the voltage set point value is reached.
•
Keep switching the tap changer higher until the bandwidth is exceeded.
The difference in the control deviation ∣ΔV(n+1) - ΔV(n)∣ at a tap setting must be smaller than double the
bandwidth.
•
Switch the voltage controller to the Auto operating mode.
After the parameterized time T1, the voltage controller should change to lower taps until the control
deviation drops below the bandwidth.
•
Switch the voltage controller back to the Manual operating mode.
Keep switching the tap changer lower until the value drops below the bandwidth. The difference in the
control deviation ∣ΔV(n-1) - ΔV(n)∣ at a tap setting must be smaller than double the bandwidth.
•
Switch the voltage controller to the Auto operating mode.
After the parameterized time T1, the voltage controller must change to higher taps until the control devi-
ation drops below the bandwidth.
Checking the Circulating Reactive Current Sensitivity in Parallel Operation
The prerequisites for correct function of the parallel operation are the commissioning of the voltage controller
in single operation and that the secondary tests have been completed.
For the functional test, the voltage controllers must be in the same parallel group according to the topology
and the Manual mode as well as the Method of minimizing the circulating reactive current must be acti-
vated. In most cases, the default setting of the parameter Reactive I control factor is sufficient, since
an optimal adjustment to the configuration takes place because of the entry of the parameter
General:Imp(Z): short circuit imp. of the transformer.
If the control deviation is still larger than double the bandwidth due to the circulating reactive current at a tap-
position difference of 1, alternating tap changing may take place. In this case, reduce the parameter Reac-
tive I control factor.
NOTE
i
i
Carry out the following tests only at low load current.
•
With all voltage controllers, approach
keep the circulating reactive current as low as possible and to reach the voltage set point value.
•
Set one of the tap changers to a higher or lower tap. This results in a circulating reactive current.
– If the difference of the circulating reactive current control deviation ∣ΔV
smaller than the set bandwidth, increase the parameter Reactive I control factor.
– If the difference of the circulating reactive current control deviation ∣ΔV
than double the bandwidth, reduce the parameter Reactive I control factor.
•
Repeat this test for all voltage controllers.
SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017
10.10 Commissioning Hints for Voltage Control
6.9.4.3 Voltage
one tap position which corresponds to the same no-load voltage to
Functional Tests
Controller.
(n+1) - ΔV (n)∣ is
actK actK
(n+1) - ΔV (n)∣ is larger
actK actK
1089