8
High Voltage Instrument Transformers | UG
User Manual
TESTS PROGRAM/
When
What
On arrival of the transformers at the warehouse or substation
A1
After unpacking
A2 - A3 - A4 - A6 - A8
During assembly
A2 - A3 - A4 – A5 - A6 - A8 - B1 - B3 - B4 - B6 - C1 - D2 - D3
After energizing
A7 - B7 - C1 - F1
Routine checks (weekly or monthly)
A2 - A7 - B7 - C1
Annual checks
A2 - A3 - A4 - A5 - A6 - A7 - A8 - B1 - B3 - B4 - B6 - B7 - C1 - F1
After re-connections, the load changes
A7 - B1 - B3 - B4 - B6 - B7 - F1
After the fault conditions, the short circuits, etc.
A3 - A7 - B1 - B3 - B4 - B6 - C1
See also “Careful check of the transformer” below.
After 1 year from start-up and after 5 years from start-up, if the
values are normal and there is no considerable increase, perform
an analysis after 15 years from start-up, and then every 5 years
E1 - E2 - E3
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
Control item
Cause
Countermeasure
Abnormal
voltage
indication
› Visual control
› Load control
› Measuring insulation
resistance
› Analyzing gas
Internal issue
Contact ARTECHE
Partial discharges
Short circuit
alarm in the
secondary
Ferro-resonance
Loss of contacts
Repairing the issue
Contact ARTECHE
1. Equipment name
2. Serial number
3. Type
4. Manufacture date
5. Description of the issue
6. Results of the controls
Strange
noises,
smells and
vibrations
Winding short-circuit
Contact ARTECHE
Winding error
Relay trip
and non-trip
Overload
Correct loading
Gas pressure
drop
› Locate gas leaks
› Determine pressure losses
Deteriorated sealing
Contact ARTECHE
Surface corroded
by the
sealing parts
Oxidation
and
corrosion
› Visual check
› Examine environment
Peeled-off coating
Repainting
Corrosive atmosphere
Insulation
loss
Wet or contaminated
Clean and dry off.
If the resistance
is not restored in
spite of your efforts,
contact ARTECHE
