Howard HI-110 User Manual
Network Transformer Instruction Manual
Document 2.4.128, Revision 2
August, 2012
Instructions (HI-110)
Installation, Operation, and Maintenance
of Secondary Network Transformers
Howard Industries
Distribution Transformer Division
1
Document 2.4.128, Revision 2
August, 2012
READ THIS IMPORTANT SAFETY INFORMATION
Read these instructions carefully and become familiar with the equipment before
proceeding with installation, operation, or maintenance activities. This equipment
contains extremely hazardous voltages. To prevent death, serious personal
injury, or equipment damage, all information in these instructions should be read
and observed. Safe use of this equipment is dependent on proper installation,
operation, and maintenance procedures.
Certain information in this manual is marked with the words DANGER, WARNING, or
CAUTION, which indicate hazards.
• DANGER indicates an imminently hazardous situation which, if not avoided, will
result in death or serious personal injury and may also result in damage to the
equipment.
• WARNING indicates a potentially hazardous situation which, if not avoided, could
result in death or serious personal injury and may also result in equipment
damage.
• CAUTION indicates a potentially hazardous situation which, if not avoided, could
result in minor or moderate personal injury and may also result in damage to the
equipment.
Network Transformer Instruction Manual
Personnel should not attempt to service this equipment until it has been effectively
de-energized, and all high-voltage and low-voltage bushing terminals have been
properly grounded. Only qualied personnel should install, maintain, and operate
this equipment. Qualied personnel are those who are trained in the installation,
maintenance, and operation of high-voltage equipment, trained in the proper use
of personal protective equipment (such as rubber gloves, safety glasses, protective
clothing, hard hats, etc.) and trained in appropriate rst aid procedures.
The instructions contained herein are intended to be a general guide for the
installation, operation and maintenance of this equipment, when operated in
“Usual Service Conditions” as dened in IEEE Standard C57.12.00. Although efforts
have been made to ensure accuracy and completeness, these instructions do not
address every conceivable application or circumstance that might be encountered.
Features presented herein may not be present in all equipment designs. Standard
and optional features are subject to change without notice. Howard Industries
makes no representation or warranty with respect to and assumes no responsibility
for the completeness, accuracy, sufciency, or usefulness of these instructions.
These instructions do not cover the installation, operation or maintenance of the
secondary network protector or any other accessory equipment installed by the
user. Users should refer to instructions provided by the manufacturer of such
equipment.
Questions regarding installation, operation, and maintenance, particularly when
encountering unusual or special circumstances not sufciently covered by these
instructions, should be directed to the Howard Industries Transformer Division.
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Network Transformer Instruction Manual
Document 2.4.128, Revision 2
August, 2012
Table of Contents
SECTION 1: INTRODUCTION .............................................................................................................................5
SECTION 2: RECEIVING, HANDLING AND STORAGE ......................................................................................6
Drawings and Documents ...............................................................................................................................6
Lifting and Handling .........................................................................................................................................6
Initial Inspection ................................................................................................................................................6
Fluid Levels ........................................................................................................................................................7
Internal Inspection ...........................................................................................................................................7
Fluid Sampling ...................................................................................................................................................7
Transformer Storage ........................................................................................................................................7
SECTION 3: INSTALLATION ...............................................................................................................................9
Lifting and Handling .........................................................................................................................................9
Jacking ...............................................................................................................................................................9
Location and Mounting ....................................................................................................................................9
Grounding ........................................................................................................................................................10
Primary and Secondary Connections ............................................................................................................10
Primary Connections .......................................................................................................................................10
Secondary Connections ..................................................................................................................................10
SECTION 4: INSPECTION AND TESTING ....................................................................................................... 11
Pre-Energization Inspection and Tests ......................................................................................................... 11
Continuity and Winding Resistance Test ...................................................................................................... 11
Ratio Test ........................................................................................................................................................ 11
Insulation Resistance Test............................................................................................................................. 11
Tap Changer Setting ....................................................................................................................................... 12
Series/Multiple and Delta/Wye Switch Settings .......................................................................................... 12
Grounding ....................................................................................................................................................... 12
Bolted Connections ........................................................................................................................................ 12
Fluid Levels ..................................................................................................................................................... 12
Fluid Temperature .......................................................................................................................................... 12
Current Transformers ..................................................................................................................................... 12
Accessory Wiring ............................................................................................................................................ 12
Tank Finish...................................................................................................................................................... 12
Tools ................................................................................................................................................................ 12
Internal Inspection ......................................................................................................................................... 12
Post-Energization Inspection and Tests ........................................................................................................ 13
Verifying Correct Voltage ................................................................................................................................ 13
Checking for Leaks ......................................................................................................................................... 13
Observing Operation ...................................................................................................................................... 13
Checking Gauges ........................................................................................................................................... 13
Audible Sound ................................................................................................................................................ 13
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Document 2.4.128, Revision 2
August, 2012
Network Transformer Instruction Manual
SECTION 5: OPERATION OF SWITCHING AND PROTECTIVE DEVICES ..........................................................14
Tap Changer .....................................................................................................................................................15
Series/Multiple or Delta/Wye Switch .............................................................................................................15
Primary Disconnect and Grounding Switch Computer Support .....................................................................16
Three-Position Non-Interrupting Primary Disconnect and Grounding Switch ............................................... 16
Three-Position Mag-Break Primary Disconnect and Grounding Switch......................................................... 16
Sequential Grounding Provisions ..................................................................................................................... 17
Phase Sequence Identication Provisions ..................................................................................................... 17
Network Protector ............................................................................................................................................. 17
Other Switching and Protective Devices .......................................................................................................... 17
SECTION 6: ACCESSORIES ...............................................................................................................................18
Diagrammatic Nameplate ................................................................................................................................18
Fluid Level Gauge .............................................................................................................................................18
Fluid Temperature Gauge ................................................................................................................................18
Filler Plug and Upper Filter Press Connection .................................................................................................18
Combination Drain and Bottom Filter Valve .................................................................................................... 18
Terminal Chamber Vent and Level Plug ........................................................................................................... 18
Air Test Provision ...............................................................................................................................................19
Automatic Pressure Relief Valve and Pressure Relief Device .......................................................................19
Primary Entrance .............................................................................................................................................. 19
High-Voltage Bushings .....................................................................................................................................19
Secondary Bushings .........................................................................................................................................20
Current Transformers ........................................................................................................................................20
Other Accessory Devices ..................................................................................................................................20
SECTION 7: MAINTENANCE .............................................................................................................................. 21
Periodic Inspection............................................................................................................................................21
Inspection and Maintenance Checklist ........................................................................................................... 21
Electrical Testing ............................................................................................................................................... 22
Exterior Paint Finish ..........................................................................................................................................23
Fluid Leaks ........................................................................................................................................................23
Audible Sound Level..........................................................................................................................................23
Other Accessory Devices ..................................................................................................................................24
Sampling and Testing the Fluid ....................................................................................................................... 24
Filtering the Fluid ..............................................................................................................................................24
Removing or Lowering the Fluid .......................................................................................................................24
Filling with Fluid ................................................................................................................................................ 24
Opening the Transformer Tank ........................................................................................................................25
Torque Guidelines ............................................................................................................................................. 25
Additional Maintenance Instructions .............................................................................................................. 27
Repair Parts ...................................................................................................................................................... 27
Warranty Claims ............................................................................................................................................... 27
TABLES
Table 1: Mag-Break Primary Switch Operation ...............................................................................................16
Table 2: Sequential Grounding Switch Operation ........................................................................................... 17
Table 3: Torque Guidelines for External Cabinet Fasteners ........................................................................... 26
Table 4: Torque Guidelines for External Bushing Mounting Hardware ..........................................................26
Table 5: Torque Guidelines for External Bushing Terminal Connections .......................................................26
Table 6: Torque Guidelines for Accessories ..................................................................................................... 27
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Network Transformer Instruction Manual
SECTION 1: INTRODUCTION
This document is intended as a general guide for
the installation, operation and maintenance of
Howard Industries secondary network transformers.
Although efforts have been made to ensure accuracy
and completeness, these instructions do not address
every conceivable application or circumstance that
might be encountered. Features presented herein
may not be present in all transformer designs.
Standard and optional features are subject to
change without notice. Howard network transformers
are designed in accordance with IEEE Standard
C57.12.40, Secondary Network Transformers,
Subway and Vault Types (Liquid Immersed)Requirements.
Document 2.4.128, Revision 2
August, 2012
The instructions contained herein are applicable
to transformers operated in normal conditions as
specied in the “Usual Service Conditions” section
of IEEE Standard C57.12.00. Questions regarding
installation, operation, and maintenance (particularly
when encountering unusual or special circumstances
not sufciently covered by these instructions) should
be directed to the Howard Industries Transformer
Division.
IT IS IMPORTANT TO READ AND COMPLY WITH
ALL SAFETY INFORMATION, INSTRUCTIONS AND
WARNINGS DISPLAYED THROUGHOUT THESE
INSTRUCTIONS BEFORE ATTEMPTING ANY
INSTALLATION, OPERATION, OR MAINTENANCE
ACTIVITIES.
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Document 2.4.128, Revision 2
August, 2012
SECTION 2: RECEIVING, HANDLING AND STORAGE
Drawings and Documents
Locate all shipping papers, packing lists, outline
drawings, and other pertinent information for use
during inspection. The transformer outline drawing
indicates the location of nameplates and provides
physical dimensions and weights. The nameplate
provides electrical characteristics, winding
connections, and weights. The wiring diagram
provides details of any control and alarm wiring that
might have been supplied.
Lifting and Handling
Lifting hooks are provided on the sides of the
transformer tank near the tank cover. All four lifting
hooks must be used simultaneously for lifting. The
transformer must not be lifted from any points other
than the provided lifting hooks. Do not use holes in
the lifting hooks for lifting. These holes are for tiedown purposes only, and are not suitable for lifting.
Do not use the cover-mounted lifting eyes for lifting
the entire transformer, as these lifting eyes are
suitable for lifting the cover plate only.
Transformers should be lifted in an upright position,
allowing no more than 15 degrees of tilt from
vertical. Lifting cables should be no more than 20
degrees from vertical. Spreader bars should be used
to keep the lifting cables nearly vertical, enabling
a safe lift and reducing the likelihood of tank
deformation or damage to painted surfaces.
Lifting the transformer with a forklift is not
recommended, since weight and balance can be
problematic and radiator panels can be easily
damaged. Refer to the transformer nameplate
to determine the total weight of the assembled
transformer. Special care must be taken when
handling transformers when the ambient
temperature is below minus 20°C (minus 4°F);
otherwise, permanent damage to the transformer
may result.
Initial Inspection
Although all transformers, components, and
accessories are carefully inspected and tested
prior to shipment from the factory, a thorough
receiving inspection should be conducted to detect
Network Transformer Instruction Manual
WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW COULD RESULT IN DEATH OR
SERIOUS PERSONAL INJURY AND MAY ALSO
RESULT IN DAMAGE TO THE EQUIPMENT.
• Use a crane, suitable lifting cables or
straps, and a spreader bar to unload the
transformer.
• Do not unload using a forklift. Keep
unnecessary personnel clear while
unloading and moving the transformer.
any damage or loss that might have occurred after
shipment. The receiving inspection should be
completed upon receipt and before unloading from
the truck. Note any damage or discrepancies on the
bill of lading, le a claim with the carrier, and notify
the Howard Industries Transformer Division prior to
unloading the transformer and before attempting any
repair.
Before unloading the transformer, the following
checks should be performed:
1. Read the serial number on the transformer
nameplate and make sure it matches the
serial number listed on the bill of lading. Also,
check the nameplate for kVA rating, primary
voltage rating, secondary voltage rating,
impedance and other design characteristics,
and make sure they comply with the
specications.
2. Check shipping documents to make sure
the shipment is complete, including all listed
accessories and hardware. Be aware that
additional items may arrive on separate
pallets. Claims for shortages or errors
must be noted on the shipping documents
and reported immediately to the Howard
Industries Transformer Division. Failure to
make a timely claim will constitute unqualied
acceptance and a waiver of all such claims by
the purchaser.
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Network Transformer Instruction Manual
Document 2.4.128, Revision 2
August, 2012
3. Check the main tank, primary switch
chamber and primary terminal chamber for
indication of uid leaks, looking carefully at
weld seams, bushings, gauges, valves and
all other main tank and chamber ttings. If
suspicious indications are found, investigate
thoroughly to determine if a leak does exist
on the transformer. Indications of a leak
can sometimes be residual uid that was not
cleaned during the manufacturing process
and not an actual leak. In many cases a small
pinhole tank leak or leak from a bushing,
gauge, valve or other tting can be easily
repaired on site. Refer to the “Maintenance”
section for information about the repair of
uid leaks.
4. Check for external damage including dents or
scratches on the main tank walls, radiators,
primary switch chamber and primary terminal
chamber. Dents and scratches can often
be repaired on site using simple touch-up
procedures. If touch-up painting is performed,
do not remove or obscure any warning labels,
instructional labels or nameplates.
5. Check for broken, cracked, or damaged
bushings, gauges, valves and other ttings
and accessories.
same type of liquid as specied on the transformer
nameplate. If uid must be added, refer to “Filling
with Fluid” for instructions.
Internal Inspection
An internal inspection of the transformer is rarely
WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS BELOW
COULD RESULT IN DEATH OR SERIOUS PERSONAL
INJURY AND MAY ALSO RESULT IN DAMAGE TO
THE EQUIPMENT.
• Do not energize the transformer if the uid
level is low.
• Maintain proper uid level while the
transformer is energized.
necessary and is recommended only when there
are obvious indications that the transformer
has received severe impact damage during
transit. Do not open the transformer main tank
without authorization from the Howard Industries
Transformer Division. If the transformer main tank
must be opened, refer to “Opening the Transformer
Tank” for instructions.
6. Check for missing or damaged component
parts that may have shipped separately from
the transformer.
Fluid Levels
The transformer and primary switch chamber are
shipped from the factory with insulating uid lled
to the proper level. When provided, the primary
terminal chamber is also lled with uid at the
factory when the transformer is equipped with deadfront separable insulated bushings or bushing wells.
Before energizing the transformer, verify proper uid
levels by observing the uid level gauges. The uid
level gauge pointer should be between the “High”
and “Low” mark, and point approximately at the
25°C mark.
A transformer found to have a low uid level
should be checked for potential leaks, repaired as
necessary and lled to the proper level with the
Fluid Sampling
Sampling and testing of the uid is not required
unless there is an indication that moisture or
other contaminants have accidently entered the
main tank, switch chamber, or terminal chamber
during transit. If moisture or contaminants in the
uid are suspected, contact the Howard Industries
Transformer Division immediately for instructions.
If uid sampling is required, refer to “Sampling the
Fluid” for instructions.
Transformer Storage
Transformers can be temporarily stored if properly
prepared. It is recommended that transformers
be stored completely assembled. Prior to storage
transformers should be thoroughly inspected as
described above in the “Initial Inspection” section.
If the transformer is not completely assembled,
separate components and accessories should be
stored in a clean dry area in their original shipping
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Document 2.4.128, Revision 2
August, 2012
containers. Do not store the transformer in a
corrosive environment.
If the transformer is to be stored for an extended
period of time before being placed into service,
it should be stored on a rm level surface. The
gas space above the insulating uid should be
pressurized with dry nitrogen to a pressure of 2-3
PSIG. This will prevent a negative internal pressure
that might draw moisture into the main tank, switch
chamber, or terminal chamber. Prior to storage, be
sure that the primary bushings or bushing wells
are tted with their protective dust covers, and the
secondary throat shipping guard is installed.
The transformer should be inspected periodically
while it is in storage. Ensure that an effective
pressure seal is maintained, and check for leaks
and corrosion. Any damage or defect should be
repaired immediately.
Network Transformer Instruction Manual
8
Network Transformer Instruction Manual
Document 2.4.128, Revision 2
August, 2012
SECTION 3: INSTALLATION
Lifting and Handling
Lifting hooks are provided near the top of the
transformer tank for lifting. All four lifting hooks
must be used simultaneously. The transformer must
not be lifted from any points other than the provided
lifting hooks. Do not use holes in the lifting hooks for
lifting. These holes are for tie-down purposes only
and are not suitable for lifting. Do not use the covermounted lifting eyes for lifting the entire transformer,
as these lifting eyes are suitable for lifting the cover
plate only.
Transformers should be lifted in an upright position,
allowing the transformer to tilt no more than 15
degrees from vertical. Lifting cables should be
no more than 20 degrees from vertical. Spreader
bars should be used to keep the lifting cables
nearly vertical, enabling a safe lift and reducing the
likelihood of tank deformation or damage to painted
surfaces.
Lifting the transformer with a forklift is not
recommended, since weight and balance can be
problematic and radiator panels can be easily
damaged. Refer to the transformer nameplate
to determine the total weight of the assembled
transformer. Special care must be taken when
handling transformers when the ambient
temperature is below minus 20°C (minus 4°F);
otherwise, permanent damage to the transformer
may result.
WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW COULD RESULT IN DEATH OR SERIOUS
PERSONAL INJURY AND MAY ALSO RESULT IN
DAMAGE TO THE EQUIPMENT.
• Use a crane, suitable lifting cables or
straps, and a spreader bar to unload the
transformer.
• Do not unload using a forklift.
Jacking
The transformer base is designed for jacking. Do
not use radiator ns, bushings, valves, gauges or
sheet metal surfaces for jacking. Jacking must
be done using the proper jacking provisions from
two adjacent corners simultaneously to prevent
warping of the tank bottom. Do not allow the jack to
come into contact with panel radiators. Refer to the
transformer outline drawing for the total weight of
the assembled transformer.
Location and Mounting
Consult local and national codes to ensure that
the installation meets all applicable requirements.
Location of the transformer must permit it to operate
in conditions that meet the requirements specied
in the “Usual Service Conditions” section of IEEE
Standard C57.12.00. Operation not meeting these
service condition requirements will compromise
transformer capacity and reliability, unless the
transformer is designed specically for operation
in conditions other than usual service conditions.
Contact the Howard Industries Transformer
Division, if additional information is needed about
location and mounting issues not covered by these
instructions.
The transformer should be mounted on a level
concrete foundation of sufcient strength to support
the weight of the completely assembled transformer
including the network protector and any other
attached accessories. The transformer should sit
ush with the surface of the mounting surface, so
that the transformer’s weight is evenly distributed.
The installed transformer should not tilt in any
direction more than three degrees. Greater tilt may
compromise insulation uid coverage of live parts
and may prevent insulating uid from circulating
properly through the cooling radiators. Improper
circulation of insulating uid may cause overheating
and result in reduced transformer life.
• Keep unnecessary personnel clear while
unloading and moving the transformer.
When network transformers are installed in vaults or
compartments, it is necessary to provide adequate
ventilation. The amount of air ow necessary will
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