1. CONSERVATOR :
a) Check the oil level in the conservator. If the level is
low than the optimum mark indicated on the oil level gauge,
it should be topped with proper grade of transformer oil having
suitable breakdown voltage value.
b) The tightness of the cap/plug of the oil filler pipe, drain
plug or drain valve should be checked .
c) The oil level gauge of the conservator should always be
kept clean so that the oil level is visible from a short distance.
2. BUCHHOLZ RELAY
a) The observation glasses should show that the
buchholz relay is properly filled with oil. If necessary,
bleeding can be done from the two cocks. The drain plug should
be tight and no leaking should be there.
b) The cover on the connection chamber should be opened to
observe whether connections are properly tight.
3. SHUT OFF VALVE
This should always be in fully open position while the
transformer is being energised.
a) The plug at the end of the breather pipe is to be removed
and breather fitted on to the pipe along with the fly nut.
b) It is necessary before fitting the breather to observe
the colour of the silicagel. If necessary, the breather should
be opened and the silicagel properly dried up so that its
colour is perfectly bluish.
c) The chamber at the bottom of the breather should be filled
in with dry transformer oil up to the level marked.
5. DIAL TYPE THERMOMETER
If it is provided with alarm and trip contacts, these should
be set to proper temperature before energising the transformer.
For guidance purposes, it may be mentioned here that a transformer
having temperature rise of 45/55°C, the trip contact should
be set at ambient temperature plus 45°C and the alarm
contact will be 5° - 10° prior to this.
6. WINDING TEMPERATURE INDICATOR
This will be set in the same way as the dial type thermometer
excepting that the trip contact should be set at ambient temperature
7. MARSHALLING BOX:
The windows of the marshalling box should always be kept
clean so that the readings of the oil temperature indicator
and winding temperature indicator can be easily read from
outside. Some dehydrating agent may be kept inside the marshalling
box so that the box is kept always in dry condition. Do not
keep the dorr of marshalling box open. It must be locked.
8. EXPLOSION VENT
a) In case an equaliser pipe connection is provided, the
valve in the pipe should be kept in open position before the
transformer is energised.
b) If the explosion vent is provided with an air release
device, this should be opened once to release any pressure
generated inside and then it should be closed.
c) The diaphram of the vent should be intact.