MR TAPCON 250 - Page 80

8 Commissioning
Maschinenfabrik Reinhausen GmbH 202280 8595028/00 ENTAPCON
®
250
9. Press to select auto mode on all devices.
ð All devices return the on-load tap-changers to the original tap positions.
If an on-load tap-changer does not switch back to its original tap position,
you have to increase the circulating reactive current sensitivity.
If one of the on-load tap-changers switches one or more tap positions
higher and the other switches the same amount lower, you need to reduce
the circulating reactive current sensitivity.
After you have set the circulating reactive current sensitivity, continue with
the function test for the circulating reactive current blocking limit described in
the next section.
8.3.3.2 Testing the circulating reactive current blocking limit
This section describes how to run the function test for circulating reactive
current blocking.
ü Set the circulating reactive current blocking limit to a value of 20%.
1. Press on a TAPCON® to select manual mode.
2. Using manual control, adjust the relevant motor-drive unit upwards (for ex-
ample 1...2 steps) by the maximum permitted tap difference in operating
positions between the parallel operating transformers.
When setting the circulating reactive current blocking in the following
process step, wait approximately 2 to 3 seconds between the individual
steps.
3. In the Parallel operation > Parallel operation method menu item, set
the circulating reactive current parallel operation method.
4. Reduce the circulating reactive current blocking limit parameter from the
set value of 20% in steps of 1% until the message Circulating reactive cur-
rent blocking limit exceeded is displayed.
ð Any further regulation is blocked.
ð After the set delay time for the parallel operation error message has
elapsed, the circulating reactive current blocking message is displayed.
5. Increase the circulating reactive current blocking limit parameter again un-
til the message Circulating reactive current limit exceeded disappears.
6. Press to select auto mode.
ð The motor-drive unit automatically returns to the original operating posi-
tion.
7. Set the value determined for the "circulating reactive current blocking
limit" for the TAPCON® units in parallel operation as well.