Howard Medium Power Substation User Manual
Page 3

Medium Power Substation Transformers
Document 2.4.06, Revision 4
June 2013
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IMPORTANT SAFETY INFORMATION .................................................................................................................................................................. 2
IMPORTANT INFORMATION ABOUT THESE INSTRUCTIONS ............................................................................................................................. 2
RECEIvING INSPECTION .................................................................................................................................................................................... 4
Impact Recorder .......................................................................................................................................................................................... 4
Drawings and Documents ........................................................................................................................................................................... 4
External Inspection ...................................................................................................................................................................................... 4
Tank Pressure .............................................................................................................................................................................................. 5
Moisture Test (for units shipped dry) ......................................................................................................................................................... 5
Internal Inspection ...................................................................................................................................................................................... 5
Table A: Conversion of dew point in degrees centigrade to vapor pressure in micrometers of mercury ............................................. 6
Table B: Moisture equilibrium chart showing acceptable and unacceptable moisture limits. ............................................................. 6
HANDlING .......................................................................................................................................................................................................... 7
lifting ........................................................................................................................................................................................................... 7
Jacking, Skidding, and Rolling .................................................................................................................................................................... 7
STORAGE ............................................................................................................................................................................................................. 8
Transformer Storage.................................................................................................................................................................................... 8
Extended Storage ........................................................................................................................................................................................ 8
Quarterly Inspection .................................................................................................................................................................................... 8
Annual Inspection ........................................................................................................................................................................................ 9
INSTAllATION ...................................................................................................................................................................................................10
location and Mountingw ..........................................................................................................................................................................10
Opening Transformer Tank ........................................................................................................................................................................10
Installation of Detachable Radiators .......................................................................................................................................................11
Filling Installed Radiators with Fluid ........................................................................................................................................................12
Installation of High-voltage Bushings ......................................................................................................................................................12
Installation of Draw-lead Bushings .........................................................................................................................................................12
Installation of Condenser Bushings .........................................................................................................................................................13
vacuum Oil Fill Process .............................................................................................................................................................................13
Installation of Surge Arresters .........................................................................................................................................................................14
Installation of Air Terminal Chamber and 15kv or 5kv Switchgear Adapters .......................................................................................14
Pre-energization Tests and Checklist .......................................................................................................................................................14
COMPONENTS AND ACCESSORIES .................................................................................................................................................................16
Transformer Nameplate ............................................................................................................................................................................16
Control Cabinet ..........................................................................................................................................................................................16
Alarm Switch Ratings ................................................................................................................................................................................16
Current Transformers ................................................................................................................................................................................16
Pressure/vacuum Gauge ..........................................................................................................................................................................16
Automatic Pressure Relief Device ............................................................................................................................................................16
Fluid level Gauge ...................................................................................................................................................................................... 17
Fluid Temperature Gauge ......................................................................................................................................................................... 17
Winding Temperature Gauge .................................................................................................................................................................... 17
Thermal Overload Relay ............................................................................................................................................................................ 17
Rapid Pressure Rise Relay ........................................................................................................................................................................ 17
Transformer Cooling Fans .........................................................................................................................................................................18
De-Energized Tap Changer........................................................................................................................................................................18
Dual-voltage or Delta/Wye Switch ...........................................................................................................................................................18
On-load Tap Changer ................................................................................................................................................................................19
High-voltage Bushings ..............................................................................................................................................................................19
low-voltage Bushings ...............................................................................................................................................................................19
Surge Arresters ..........................................................................................................................................................................................19
Radiators ....................................................................................................................................................................................................19
MAINTENANCE .................................................................................................................................................................................................20
Periodic Tests and Inspections .................................................................................................................................................................20
Sampling of Insulation Fluid ....................................................................................................................................................................20
Gaskets ......................................................................................................................................................................................................21
Additional Maintenance Instructions .......................................................................................................................................................21
Repair Parts ...............................................................................................................................................................................................21
Warranty Claims ........................................................................................................................................................................................21
TABlE OF CONTENTS