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Transformer Commisioning1. Check connection diagram, voltage
ratio and rating plate. 2. Establish the right transformer ratios
byusing tap changer.3. Measure insulation between:
a) separate windingsb) winding and earth
4. Look for possible break downs at the transformer terminals by
means of an ohm-meter.5. Check connecting of transformer and phase
equality.6. When working in parallel, transformers ought to have
the same vector group, same conversion rate,same frequency and same
impedance voltage. The rating ratio between parallel transformers
should notexceed 3:17. Connect earthing cable.8. Put all three-way
valves, vents and gaskets in operation condition. See appendices.
9. Adjust arcinghorns on bushings.10. De-aerate a) radiators
b) bushingsc) Buchholz relay
11. Check thermometer pockets.12. Check air dryer, if need be,
change drying salt (silica gel).13. Check oil level of conservator
and add oil if needed.14. Connect control equipment according to
connection diagram and earth it carefully.15. Adjust control
units.16. Test all control units.17. Connect Buchholz relay in such
a way that, when operating, the transformer always disconnects via
HVand LV-side.*18. Connect and earth motor drive of on-load tap
changer according to its connection diagram.*19. Test tap changer
on load switch.
1) Before connecting the auxiliary supply:- Check conformity
position indicator in motor drive unit and on the on-load
tap-changer. -Control of the mechanical disengaging at the end
positions.Turn motor drive by means of lever through the end
positions, after 2 to 3 revolutions: disengage.- Control voltage
of: motor, control circuit and heating circuit.- Check feeding
voltage and phase sequence, then connect according to diagram
(right rotatingfield).
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-Test electrical end-position locking.-Test step-by-step
operation.Keep push button S1 or S2 down: only 1 tap change may be
accomplished.- During a tap change, disconnect motor switch al by
means of emergency switch S5 (S9) andreconnect al: connection runs
on.-Test safe-guards against wrong rotating field.Interchange two
phases, give an impulse with push-button S1 or S2; after 2 to 3
revolutions disconnection of motor switch 01.-Test working of
heating and/or thermostat and/or hygrostat.- Remote control:
control if the raise and lower push-buttons on the transformer
agree with thepush-buttons and contacts of the automatic voltage
regulator.
2) Put the on-load tap changer into operation.*20. The
protective relay of the tap changer should be connected in such a
way that, when called upon,the transformer always disconnects via
HV- and LV side. After service put the relay back in
"Operatingposition" (see directions for use of the relay).21. Now
the transformer may be put under voltage.22. After heating up the
transformer, disconnect once more and check all gasket
screws.Remark:The numbers marked with * are not required in case a
manual off-load tap changer is used.
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