ABB Power Grids Ltd.
GKSL 680205.021 RE
Rev. 2, 26.09.2019
6
Figure 1 shows the bushing components. The main insulation of the bushing consists of an insulating body
(pos. 1) made from under vacuum resin impregnated paper with aluminium layers for capacitive grading
and wound on the copper or brass rod (pos. 2).
A porcelain insulator (pos. 3) is pressed to the flange (pos. 4) with a spring system in the top part of the
bushing (pos. 5). To protect the insulator body from moisture, the space between the body and the porcelain
insulator is filled with the compressible dry filler Micagel.
For the measurement of the capacitance, the dissipation factor and PD of the bushing a self grounding test
tap (pos. 6) is installed in the main flange. Due to a design of the test tap the last aluminium layer is grounded
automatically in use if the cover is screwed upon it.
Never open the test tap during the operation!
5 Marking
On the every bushing flange there is a designation plate with following information:
manufacturer’s trade mark;
country;
the bushing’s identifying code;
dimensional drawing number;
production serial number;
voltage and current rating;
weight;
maximum installation angle in relation to vertical;
C
1
and tg
δ
1
;
C
2
and tg
δ
2
.
6 Packaging, transportation and storage
6.1 Shipment
Bushings are transported in wooden boxes rigidly fixed with elastic packing cradles. The top of the box is
marked with “Top”. Bushings are shipped and stored horizontally. The low part of bushing is protected
from moisture by a plastic case with a silica gel bag inside.
While storing plastic cases and silica gel bags are checked for consistency once in six months. A change of
indicating silica gel color from blue to pink points at its silica gel’s being damp. In this case the whole silica
gel must be changed.
6.2. Storage rules
Bushings can be stored outdoors only in weatherproof places or indoors. Storage time (short, medium or
long period, see Table 2) should be taken into consideration.
Caution! Generally the moisture protection of the bushing must be mounted all times.
