8
High Voltage Instrument Transformers | DDB/DFK/DDN/DFN
User manual
TESTS PROGRAM/
CAREFUL CHECK OF THE TRANSFORMER/
It is recommended that all regular tests be repeated after a
long period of operation (about 20 years), or if a major network
disturbance has occurred that could damage the transformer
(e.g. a short circuit with current or duration values higher
than the nominal ones, or over-voltages caused by the
malfunctioning of the switches).
QUICK TROUBLESHOOTING GUIDE
Phenomenon
Cause Countermeasure
Oil stains
Oil residues from the
manufacturing process
Clean the area and keep it under observation
for 24 hours. If the stain does not reappear,
the device can function normally. If the
leak persists, contact ARTECHE
Loose junctures
Tighten the screws and bolts, clean the
area and keep it under observation.
If the leak persists, contact ARTECHE
Cracks or damage to components
Contact ARTECHE
Non-visible oil level
Oil leakage or overpressure
Remove the transformer from
service and contact ARTECHE
Cracks in resin parts
Blows or improper handling
Contact ARTECHE
When
What
On arrival of the transformers at the warehouse or substation
A1
After unpacking
A2 - A3 - A4 - A6 - C2
During assembly
A2 - A3 - A4 – A5 - A6 - B1 - B3 - B4 - B6 - B8 - C1 - C2 - D2 - D3
After energizing
A7 - B7 - C1 - C2 - F1
Routine checks (weekly or monthly)
A2 - A7 - B7 - C1 - C2
Annual verifi cations
A2 - A3 - A4 - A5 - A6 - A7 - B1 - B3 - B4 - B6 - B7 - B8 - C1 - C2 - F1
Every fi ve yea
Same as D1
After re-connections, load changes
A7 - B1 - B3 - B4 - B6 - B7 - B8 - F1
After the fault conditions, the short circuits, etc.
A3 - A7 - B1 - B3 - B4 - B6 - B7 - B8 - C1 - C2 - D1
See also “Careful check of the transformer” below