Ormazabal PREFORMA-PF-4, General Instructions Manual

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GENERAL INSTRUCTIONS FOR PREFORMA PF-4 / 5
ASSEMBLY AND USE OF PREFABRICATED PRIVATE
SUBSTATIONS (LV METERING)
IG-138-FR
version 02
02.10.2007
Page 17 of 28
4.4. EARTHING CIRCUITS
4.4.1. Excavation Bottom Earth
Under the installer's responsibility: the substation is earthed before the substation is placed.
It is to be connected to the conductive parts’ connection device in accordance with the
regulatory provisions in force.
5. REPLACEMENT OF THE SWITCHGEAR
After application of the regulations in force, switchgear replacement operations are possible
through the substation's doors. These operations are executed by authorised staff, under the
responsibility of the principal.
5.1. REPLACEMENT OF THE TRANSFORMER

With the transformer and MV and LV cables powered down and earthed, remove the
cover’s lid and the interlocking of the MV plugs. Keep the components.
 Disconnect the MV, LV links and the transformer's Earthing components according to the
manufacturer's instructions [
3
] .
 Remove the transformer's holding slings. Replace the transformer.
 At the end of the operation, you must put back the earth connections as they were
originally.
5.2. REPLACEMENT OF THE MV BOARD
 Disconnect the MV boards following the manufacturer's recommendations:
Dismount the fixture points of the MV board to be replaced (the rear of the board is not fixed
by screws but held in place by two peaks, which enables the board to be pulled forward
unhindered, once the fixing screws are removed. It is important to leave the rails embedded
in the floor in place).
 Remove the MV board and replace it.
5.3. REPLACEMENT OF THE TGBT
The TGBT board is fixed onto the vertical rails and to the ground.
 The powered down TGBT:
- Disconnect the board's outputs and inputs.
-
Disconnect the LV auxiliary supply board.
- Disconnect the TGBT's earthing bridges.
- Dismount the TGBT's fixture points.
 Remove the TGBT and replace it making any required adjustments to the vertical rails.
[3]
See paragraph 1.3
N.B. : There is a low point (left, front corner) for the placement of a pump strainer for oil
recovery.