ABB TCC300, User Manual, Page: 167 / 716

4.10.4.2 Motor Current Profile
The TCC300 Tapchanger Control measures the motor current during tapchange
operation. The motor current is sampled at 64 samples per cycle and the total RMS value
of the current is computed every cycle (60 Hz or 50 Hz cycle). The dynamic range of the
current measurement is from 0 to 10 A.
The tapchange start signal is generated when the motor current exceeds a threshold value
(user programmable or fixed at a small value such as 0.1 A). The tapchange operation is
considered complete when the counter contact input is generated. If the tapchanger is
making multiple tapchanges where the current is not interrupted between tapchanges then
the counter contact can be used to decide the completion of one tap before the start of the
next tap.
The following parameters are logged for the motor current profile:
• Average RMS value of the motor current (once every cycle for the complete duration
of the tapchange)
• Total duration of the tapchange in ms
• Peak RMS value of the motor current
The Sequence of Events Recorder will trigger when any of the following conditions occur:
The average RMS current is the average of the RMS current for the
tapchange duration.
• Peak RMS current exceeds a certain percent (programmable from 110% to 200%) of
the stored peak current which was recorded during the training mode.
• Average RMS current exceeds a certain percent (programmable from 110% to 200%)
of the stored average RMS current which was recorded during the training mode.
• Total duration of the tapchange exceeds a certain percent (programmable from 110%
to 200%) of the stored value which was recorded during the training mode.
The training mode will be used during the commissioning of the Tapchanger Control. In
this mode twenty tapchange operations will be manually conducted and the average
profile stored in non
‑
volatile memory. This profile will be compared with the profile
during normal tapchange operation to trigger the Sequence of Events Recorder when the
above conditions occur.
1VAC388793-MB A
Section 4
TCC600
TCC300 161
User Manual