Howard HI-102 User Manual

Fluid-Filled Overhead Distribution Transformers

Document 2.4.95, Revision 0

May, 2013

Instructions (HI-102)

Installation, Operation and Maintenance of Fluid-Filled Overhead Distribution Transformers

Howard Industries

Distribution Transformer Division

Document 2.4.95, Revision 0 May. 2013

! READ THIS IMPORTANT SAFETY INFORMATION

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READ THIS ENTIRE INSTRUCTION MANUAL CAREFULLY AND BECOME FAMILIAR WITH THE EQUIPMENT AND ALL SAFETY-RELATED INFORMATION BEFORE PROCEEDING WITH INSTALLATION, OPERATION, OR MAINTENANCE ACTIVITIES.

Safe use of this equipment is dependent on proper installation, operation, and maintenance procedures. Follow all applicable local and national codes.

Do not attempt to service or perform maintenance activities on the equipment until it has been effectively de-energized, and all high-voltage and low-voltage bushing terminals have been properly grounded. Do not rely solely on fuse removal or switch position as conclusive indication that a transformer is de-energized. Be absolutely certain that a transformer is de-energized by checking for zero voltage on all terminals.

Only qualied personnel should install, maintain, and operate this equipment. Qualied 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 (PPE) and trained in appropriate rst aid procedures. Refer to NFPA 70E.

Fluid-Filled Overhead Distribution Transformers

Certain information in this manual is marked with the words DANGER, WARNING, or CAUTION, which indicate hazards as listed below.

DANGER indicates an imminently hazardous situation which, if not avoided, will result in death

or serious personal injury, and could 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 could also result in damage to the equipment.

CAUTION indicates a potentially hazardous situation which, if not avoided, could result in minor

or moderate personal injury, and could also result in damage to the equipment.

These instructions are intended as a general guide for the installation, operation and maintenance of the equipment, when operated in “Usual Service Conditions” as dened in IEEE Standard C57.12.00.

Although every effort has been made to ensure accuracy and completeness, these instructions do not address every conceivable application or circumstance that might be encountered. Howard Industries makes no representation or warranty with respect to, and assumes no responsibility for the completeness, accuracy, sufciency, or usefulness of, these instructions. Features presented herein may not be present in all equipment designs. Standard and optional features are subject to change without notice.

Questions regarding installation, operation, and maintenance of the equipment, particularly when encountering unusual or special circumstances which may not be sufciently covered by these instructions, should be directed to the Howard Industries Transformer Division.

Document 2.4.95, Revision 0

Fluid-Filled Overhead Distribution Transformers

May, 2013

TABLE OF CONTENTS

IMPORTANT SAFETY INFORMATION ................................................................................................................................2

SECTION 1: INTRODUCTION ..............................................................................................................................................5

SECTION 2: RECEIVING, HANDLING, AND STORAGE .....................................................................................................6

Drawings and Documents ...........................................................................................................................................6

Lifting and Handling ..................................................................................................................................................... 6

Initial Inspection ............................................................................................................................................................ 6

Fluid Level ......................................................................................................................................................................7

Internal Inspection ....................................................................................................................................................... 7

Fluid Sampling ...............................................................................................................................................................7

Transformer Storage ....................................................................................................................................................7

SECTION 3: INSTALLATION ................................................................................................................................................9

Lifting and Handling ..................................................................................................................................................... 9

Location and Mounting ................................................................................................................................................ 9

Grounding ....................................................................................................................................................................10

High-Voltage and Low-Voltage Connections ..............................................................................................................10

Reconguring the Internal Low-Voltage Connections ...............................................................................................10

SECTION 4: INSPECTION AND TESTING .........................................................................................................................11

Pre-Energization Inspection and Tests ......................................................................................................................11

Ratio Test .....................................................................................................................................................................11

Insulation Resistance Test..........................................................................................................................................11

Multiple-Voltage Switch Setting ..................................................................................................................................11

Tap Switch Setting .......................................................................................................................................................11

Grounding ....................................................................................................................................................................12

Bolted Connections. ....................................................................................................................................................12

Fluid Level ....................................................................................................................................................................12

Fluid Temperature .......................................................................................................................................................12

Internal Fault Detector ................................................................................................................................................12

Current Transformers. .................................................................................................................................................12

Accessory Wiring .........................................................................................................................................................12

Tank Finish ..................................................................................................................................................................12

Internal Inspection ......................................................................................................................................................12

Post-Energization Inspection and Tests .....................................................................................................................12

Verifying Correct Voltage .............................................................................................................................................12

Checking for Leaks. .....................................................................................................................................................13

Observing Operation ...................................................................................................................................................13

Checking Gauges ........................................................................................................................................................13

Audible Sound .............................................................................................................................................................13

SECTION 5: OPERATION OF SWITCHING AND PROTECTIVE DEVICES .......................................................................14

Hot-Stick Operable Devices ........................................................................................................................................14

Taps and Multiple-Voltage Windings ..........................................................................................................................14

Tap Switch....................................................................................................................................................................15

Multiple-Voltage Switch ..............................................................................................................................................15

Fuses ...........................................................................................................................................................................15

Internal Weak-Link Fuse .............................................................................................................................................16

Partial-Range Current-Limiting Fuse ..........................................................................................................................16

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Fluid-Filled Overhead Distribution Transformers

Surge Arrester .............................................................................................................................................................16

External Surge Arrester ...............................................................................................................................................16

Internal Surge Arrester................................................................................................................................................16

Low-Voltage Circuit Breaker........................................................................................................................................17

Magnex Interrupter .....................................................................................................................................................17

Other Switching and Fusing Devices ..........................................................................................................................18

SECTION 6: OPERATION OF BUSHINGS, GAUGES AND ACCESSORY DEVICES ........................................................19

Hot-Stick Operable Devices ........................................................................................................................................19

Pressure-Vacuum Gauge ............................................................................................................................................19

Fluid Level Gauge and Sight Plug ..............................................................................................................................19

Fluid Temperature Gauge ..........................................................................................................................................19

Drain Valve and Sampling Device ..............................................................................................................................20

Automatic Pressure Relief Valve ...............................................................................................................................20

Internal Fault Detector ...............................................................................................................................................20

Bushings and Terminals ............................................................................................................................................20

High-Voltage Bushings ...............................................................................................................................................21

Low-Voltage Bushings ................................................................................................................................................21

Other Accessory Devices ............................................................................................................................................21

SECTION 7: MAINTENANCE AND REPAIR ......................................................................................................................22

Periodic Inspection......................................................................................................................................................22

Inspection Checklist ....................................................................................................................................................22

Electrical Tests ............................................................................................................................................................23

Exterior Paint Finish ....................................................................................................................................................23

Fluid Leaks ..................................................................................................................................................................24

Audible Sound Level....................................................................................................................................................24

Low-Voltage Circuit Breaker........................................................................................................................................24

Magnex Interrupter .....................................................................................................................................................25

Other Accessory Devices ............................................................................................................................................25

Insulating Fluid ...........................................................................................................................................................25

Sampling the Fluid .....................................................................................................................................................25

Filtering the Fluid ........................................................................................................................................................25

Removing or Lowering the Fluid .................................................................................................................................25

Filling with Fluid ..........................................................................................................................................................25

Opening the Transformer Tank ..................................................................................................................................26

Torque Guidelines .......................................................................................................................................................26

Additional Maintenance Instructions ........................................................................................................................28

Repair Parts ................................................................................................................................................................28

Warranty Claims .........................................................................................................................................................28

Disposal ......................................................................................................................................................................28

Tables

Table 1: Torque Guidelines for External Cabinet Fasteners .....................................................................................27

Table 2: Torque Guidelines for External Bushing Mounting Hardware ....................................................................27

Table 3: Torque Guidelines for External Bushing Terminal Connections .................................................................27

Table 4: Torque Guidelines for Accessories ...............................................................................................................27

Fluid-Filled Overhead Distribution Transformers

SECTION 1: INTRODUCTION

This document is intended as a general guide for the installation, operation and maintenance of Howard Industries uid-lled, overhead distribution transformers. Although every effort has 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.

The instructions contained herein are applicable to transformers operated in usual conditions as specied 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 sufciently covered by these instructions) should be directed to the Howard Industries Transformer Division.

Document 2.4.95, Revision 0

May, 2013

IT IS IMPORTANT TO READ AND COMPLY WITH ALL SAFETY INFORMATION AND WARNINGS DISPLAYED THROUGHOUT THESE INSTRUCTIONS BEFORE ATTEMPTING ANY INSTALLATION, OPERATION, OR MAINTENANCE ACTIVITIES.

Document 2.4.95, Revision 0 May. 2013

SECTION 2: RECEIVING, HANDLING, AND STORAGE

Fluid-Filled Overhead Distribution Transformers

Drawings and Documents

Locate all shipping papers, packing lists, specications, and other pertinent information for use during inspection. Verify that the transformer is supplied with a nameplate, required warning labels, and terminal designation markings. Verify that the terminal designation markings are consistent with those on the nameplate. The transformer nameplate provides electrical characteristics, winding connections, and weights. Check the nameplate for verication of specication compliance, including voltage and kVA ratings, percent impedance, and other design characteristics. The transformer wiring diagram provides details of any control, fan and alarm wiring that may have been provided.

Lifting and Handling

Overhead transformers may be lifted by crane or hoist. Properly palletized transformers may also be lifted by a forklift truck. Refer to the transformer nameplate to determine the total weight of the assembled transformer and make sure that the lifting equipment, hooks, cables, slings and spreader bars are adequate to perform a safe lift. Do not use transformer bushings as handles, otherwise undue stress may damage the bushing and cause a uid leak. Be aware that cooling radiators, if present, are made of relatively thin metal and can be easily damaged. Special care must be taken when handling transformers, if the ambient temperature is below minus 20°C (minus 4°F); otherwise, permanent damage to the transformer may result.

A forklift truck may also be used to lift overhead transformers that are securely mounted on a shipping pallet. Lifting forks must be of sufcient length to extend completely under the pallet. Do not attempt to lift an un-palletized transformer with a forklift truck.

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WARNING

FAILURE TO FOLLOW THE INSTRUCTIONS BELOW COULD RESULT IN DEATH OR SERIOUS PERSONAL INJURY, AND COULD ALSO RESULT IN DAMAGE TO THE EQUIPMENT.

• Lifting equipment, including forklift trucks, cranes, hoists, cables, straps, lifting bolts, hoist rings and spreader bars, must be of adequate capacity to safely lift the completely assembled transformer.

• Keep unnecessary personnel clear while unloading and moving the transformer.

Initial Inspection

Although all transformers are carefully inspected and tested at the factory, a thorough receiving inspection should be conducted to detect any damage or loss that might have occurred during 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.

Lifting the transformer by crane or hoist is accomplished using the provided lifting lugs. Do not lift from any points other than the provided lifting lugs. Do not use holes in the lifting lugs for lifting. These holes are for tie-down purposes only and are not suitable for lifting. A spreader bar should be used to keep the lifting cables or slings nearly vertical, enabling a safe lift and reducing the likelihood of tank deformation or damage to painted surfaces. Transformers should be lifted in an upright position, allowing the transformer to tilt no more than 15 degrees from vertical. Lifting cables or straps should be no more than 20 degrees from vertical.

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 shipping documents. Also, check the transformer nameplate for kVA rating, high-voltage rating, low-voltage rating, impedance and other design characteristics, and make sure they comply with the specications.

2. Check shipping documents to make sure the shipment is complete, including all listed accessories and hardware. Be aware that

Fluid-Filled Overhead Distribution Transformers

Document 2.4.95, Revision 0

May, 2013

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 unqualied acceptance and a waiver of all such claims by the purchaser.

3. The tank vacuum/pressure gauge, if provided, may indicate a positive or negative reading when the transformer is received, depending on the relative temperatures of the uid and ambient air. A rising or falling reading that varies over time with ambient temperature indicates that the transformer tank is sealed effectively. If the vacuum/ pressure gauge shows a constant zero reading, this indicates the possibility of a tank leak. If this occurs, the tank should be checked carefully for leaks as indicated in the following step.

4. Check the tank for indication of uid leaks, looking carefully at weld seams, bushings, gauges, valves and all other tank 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 completely during the lling 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 and Repair” section for information about the repair of uid leaks.

5. Check for external damage including dents or scratches on the tank walls and radiators, if present. 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.

6. Check for broken, cracked, or damaged bushings, gauges, valves and other ttings and accessories.

7. Check for missing or damaged component parts and for packages that shipped separately from the transformer.

Fluid Level

The transformer is shipped from the factory with insulating uid lled to the proper level. Before energizing the transformer, verify proper uid level by observing the uid level gauge, if provided. The uid level gauge pointer should be between the “High” and “Low” marks. For transformers provided with a uid sight plug, the uid level can be directly observed if it is within acceptable range.

When checking the uid level, be aware that it is normal for the level to vary as a function of uid temperature. A transformer found to have an unusually low uid level should be checked for potential leaks and lled to the proper level with the same type of liquid as that specied on the transformer nameplate. Refer to “Filling with Fluid.”

Internal Inspection

An internal inspection of the transformer tank is rarely necessary and is recommended only when there are obvious indications that the transformer has received severe impact damage during transit or when necessary to perform recommended preenergization tests or inspections. Do not open the transformer tank without authorization from the Howard Industries Transformer Division. If the transformer tank must be opened, refer to “Opening the Transformer Tank” for instructions.

Fluid Sampling

Sampling and testing of the uid is not required unless there is indication that moisture or other contaminants have accidently entered the tank during transit. If moisture or contaminants in the uid is 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 may 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

Document 2.4.95, Revision 0 May. 2013

containers. Do not store the transformer in a corrosive environment.

Transformers may be stored in racks designed for that purpose. Transformers should not be stacked directly on top of one another, as this may damage the tank and bushings.

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. It is recommended that the transformer be inspected periodically while it is in extended storage. Ensure that an effective pressure seal is maintained, and check for leaks and corrosion. Any damage or defects should be repaired immediately.

Fluid-Filled Overhead Distribution Transformers

SECTION 3: INSTALLATION

Lifting and Handling

Document 2.4.95, Revision 0

! WARNING

▲

FAILURE TO FOLLOW THE INSTRUCTIONS BELOW COULD RESULT IN DEATH OR SERIOUS PERSONAL INJURY AND COULD ALSO RESULT IN DAMAGE TO THE EQUIPMENT.

• Lifting equipment, including forklift trucks, cranes, cables, straps, lifting bolts, hoist rings and spreader bars, must be of adequate capacity to safely lift the completely assembled transformer.

• Keep unnecessary personnel clear while unloading and moving the 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 specied 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 specically 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

Overhead distribution transformers are not designed to be tamper resistant and must be installed in a location that is secure and accessible only by authorized personnel. Allow adequate electrical clearance between all live parts and between live parts and ground points. Ensure that cooling radiators are free of obstructions.

May, 2013

Hanger brackets are usually provided for direct pole mounting of the transformer. Pole capacity must be sufcient to support the weight of the transformer. The installed transformer should not tilt in any direction more than three degrees. Greater tilt may compromise the insulating uid coverage of live parts within the tank and may prevent insulating uid from circulating properly through the cooling radiators, if present. Improper circulation of insulating uid may cause overheating and could result in reduced transformer life.

Document 2.4.95, Revision 0 May. 2013

Fluid-Filled Overhead Distribution Transformers

When specied by the user, base skids are provided for mounting the transformer on a solid, level surface, rather than on a pole. The factory may elect to provide skids for transformers whose weight exceeds the capability of pole-mounting brackets. The mounting surface must be rated to support the weight of the completely assembled transformer. Refer to the transformer nameplate for the weight of the transformer.

Grounding

The transformer must be permanently and effectively grounded according to applicable local and national codes. Ground the transformer by using the ground pads or nuts provided on the tank. Do not use hanger brackets or any other parts of the transformer for ground connections. A proper lowresistance ground connection is necessary for safe operation. Connect all available neutrals to the system neutrals.

! WARNING

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Reconguring the Internal Low-Voltage Connections

Unless otherwise specied by the user, overhead transformers with three low-voltage bushings are shipped from the factory with the internal lowvoltage winding congured for the E/2E connection (for instance, 120/240 or 240/480 Volts). If the transformer must be recongured for operation at E Volts (for instance, 120 or 240 Volts), the transformer cover must be removed and the lowvoltage leads reconnected in parallel. Connections must be tightened appropriately to prevent overheating and possible failure of the connection. Make sure the internal low-voltage leads are insulated and that they do not touch the tank, each other or any other surface. Refer to “Opening the Transformer Tank” for instructions.

FAILURE TO FOLLOW THE INSTRUCTIONS BELOW COULD RESULT IN DEATH OR SERIOUS PERSONAL INJURY, AND COULD ALSO RESULT IN DAMAGE TO THE EQUIPMENT.

The transformer must be permanently and effectively grounded at all times.

High-Voltage and Low-Voltage Connections

The transformer nameplate illustrates the internal wiring and external identication of each bushing. The transformer must be connected and operated as indicated on the nameplate. High-voltage and low-voltage bushings are provided with terminals as specied by IEEE standards for overhead transformers, or as specied by the customer. Terminals are usually suitable for connection to either aluminum or copper conductors.

Before making high-voltage and low-voltage line connections, check to make sure that all mating connector surfaces are clean and smooth. Connections must be tightened adequately to prevent overheating and possible failure of the connection. Refer to the nominal torque guidelines contained in Table 3. Avoid excessive cantilever loads on bushings, otherwise bushing or gasket damage may result.

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Howard HI-102 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual