• Connection cables and busbars may cause seals or cracks in the bushings even if there is not
any tensile force. That’s why flexible connection is recommended in all cases.
•
Have to be adjust alarm and trip relay connection of protection equipment which are on
transformer.
While doing connection, consider connection schema inside of terminal box.
• Thermometer switches should be checked and adjusted to alarm and trip values.
Recommended temperature values; Alarm: 85°C, Trip: 90°C
• Tap changer level should be choosen according to system voltage based upon rating plate value.
Tap changer level must be adjusted when transformer is de-energized. (If tap changer is not
requested on load.)
• Bushing arcing horns are scaled in factory according to standards. If any defections detected in
gaps, please scale them according to Table 2.
Table 2:
Outdoor Electrical Clearance
* Un: H.V side voltage of rated level
** All clearances are in mm.
*** Electrical clearances are given for ≤1000m. After 1000m till 3000m each 100m distance
must be increase %1,25 .
• Transformers must fasten from where they stay skid of transformer (NPU steel).
6.2.2 Earthing Connection
• The installation must be carried out according to the standards in force, to the applicable
laws and to the present instructions. The following points must be taken into consideration
when the installation is carried out.
• Connect the earthing conductors to the relative earth points on the metallic parts of the
transformer and cable boxes.
• Connections should be done strictly with suitable conductors.
• Earth resistance should be ≤ 5 Ω.
Rated Voltage
Arcing Horn Gap
Phase To Phase
Phase To Earth
0
< Un ≤
3,6
-
50
65
3,6
< Un ≤
7,2
55
100
105
7,2
< Un ≤
12
86
110
115
12
< Un ≤
17,5
110
190
195
17,5
< Un ≤
24
155
210
215
24
< Un ≤
36
220
280
325
Ulusoy Distribution Transformers Maintenance, Operation, Installation and Instruction Manual