1ZSC000562-AAX en, Rev. 1
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Technical guide VUC
21
Maintenance after 300 000 operations (guideline: 15 years). Inspection once a year.
Coarse fine regulation leakage inductance switching
When operating from the ends of the fine or the coarse
winding a high leakage inductance might appear, causing a
phase shift between the switched current and the recovery
voltage. This value has to be given when ordering a tap-
changer so that proper dimensioning is possible.
The leakage inductance value can be given in the order
data sheet or can be calculated by ABB from active part
dimensions and number of turns. For more information,
see IEC 60214-2, 2004-10, or product information
5492 0031-100.
For most transformer designs, even those with axially located
windings, the values are normally not exceeding the limits for
VUC due to the excellent breaking performance of the vacuum
interrupters. It shall however be calculated for every case.
Contact life
The contact life for VUC type of tap-changers is always
600 000 operations, regardless of the rated through-current.
The contact life is stated on the rating plate.
Standards and testing
The on-load tap-changers made by ABB fulfill the
requirements according to IEC 60214-1, 2014-05,
1)
and
IEEE C57.131-2012.
The type tests include:
– Contact temperature rise test
– Switching tests
– Short-circuit current test
– Transition impedance test
– Mechanical tests
– Dielectric tests
The routine tests include:
– Check of assembly
– Mechanical test
– Sequence test
– Auxiliary circuits insulation test
– Vacuum test
– Final inspection
1) Some tests are acc. to IEC 60214-1, 2003-02. A new revision, IEC 60214-1,
2014-05, is recently published and the tests needed to be remade due to changed
requirements will be renewed by time but all will not be renewed at the publication
date of this document.
Rating plate
Fig. 39. Example of rating plate.
