4
Installation and commissioning guide
2750 515-1 EN, REV. 14, 2020-06-26
5 Commissioning 61
5.1 Waiting time before energization ................................................................................................................................................. 61
5.2 Recommended test before energization ..................................................................................................................................... 62
5.2.1 Overview ................................................................................................................................................................... 62
5.2.2 Tightness test between transformer and bushing flange........................................................................................... 62
5.2.3 Tightness test of bushing outer terminal.................................................................................................................... 62
5.2.4 Measurement of capacitance and dissipation factor ................................................................................................. 63
5.2.5 Measurement of through-resistance.......................................................................................................................... 66
6 Maintenance 67
6.1 Recommended maintenance ...................................................................................................................................................... 67
6.2 Checking the oil-level .................................................................................................................................................................. 69
6.3 Taking oil samples ....................................................................................................................................................................... 70
7 Re-packing 73
7.1 Removal of the bushing from the transformer, draw rod ............................................................................................................. 73
7.2 Removal of horizontally installed bushings ................................................................................................................................. 76
7.3 Re-packing of the bushing........................................................................................................................................................... 78
8 Spare parts and special tools 79
8.1 Summary ..................................................................................................................................................................................... 79
8 Spare parts.................................................................................................................................................................................. 79
8 Special tools ................................................................................................................................................................................ 81
9 Disposal and environmental information 83
9.1 Overview ..................................................................................................................................................................................... 83
9.2 Disposal and recycling ................................................................................................................................................................ 83
10 References 85
10 Summary ..................................................................................................................................................................................... 85
11 Appendix 87
11.1 Measurement record ................................................................................................................................................................... 87