Ge Otef-72 User manual

Instruction Manual

INSTRUCTION MANUAL NUMBER MIITR101

INDUCTIVE VOLTAGE TRANFORMER

OTEF-72 / OTEF-123 / OTEF-145 / OTEF-245

Instruction Manual

GE Grid Solutions

Av. Nossa Senhora da Piedade, 1021

37504-358 Itajubá - MG – Brazil

AIB 01 30/10/2017 PRB TAA

AIB 00 24/11/2013 TAA TCRP

Owner revision Date Prepared Approved

Instruction Manual

Warning!

Any person involved with transport, installation, energizing, operation and maintenance of

Inductive Voltage Transformer (VT) type OTEF must read these instruction prior to any action

related to these voltage transformers.

These VT is built under strict conditions which guarantee the Highest Quality achievement. In

order to keep this high quality during VT’s lifetime, it is utmost important that the instructions in

this Book be thoroughly read and complied with.

THESE VOLTAGE TRANSFORMERS CAN NOT BE STORED IN A HORIZONTAL POSITION FOR MORE

THAN FOUR MONTHS.

IN CASE OF HORIZONTAL TRANSPORTATION, IF THE TIME OF TRANSPORT AND STORAGE

EXCEEDS FOUR MOUNTHS, IT IS MANDATORY TO UNPACK THE VT AND FIX IT TO THE GROUND.

Preliminary Remarks

During reception of the VT, it is important to check unpacking attentively to control the condition

of the transport crate and transformer itself. Any irregularities should be recorded on the

transport delivery note a formal communication sent to the responsible person immediately.

The supplied insulator can be made of porcelain, avoid sudden movements that could cause

damage due to cracks for example.

Instruction Manual

INDEX

1. GENERAL DRAWING ................................................................................................................... 5

2. TRANSPORT, RECEPTION, UNPACKING AND STORAGE .................................................................... 6

2.1. Transport ........................................................................................................................... 6

2.2. Reception ........................................................................................................................... 6

2.3. Unpacking .......................................................................................................................... 7

2.4. Storage .............................................................................................................................. 9

3. ANCHORING .............................................................................................................................. 9

4. CONTACT SURFACES PREPARATION .............................................................................................. 9

5. CONECCTIONS............................................................................................................................ 9

5.1. Primary terminal ................................................................................................................. 9

5.2. Secondary terminals ............................................................................................................ 9

5.3. Terminal marking .............................................................................................................. 10

5.4. Grounding ........................................................................................................................ 10

6. BELLOWS BLOCKING SYSTEM FOR TRANSPORTATION ................................................................... 10

7. OIL LEVEL INDICATOR................................................................................................................ 11

8. INSPECTION BEFORE FIRST ENERGIZING ...................................................................................... 11

9. MAINTAINENCE AFTER ENERGIZING ........................................................................................... 12

10. TESTS AT SITE ....................................................................................................................... 12

11. FINAL DISPOSAL OF THE TRANSFORMER PARTS AFTER LIFETIME ................................................ 12

Instruction Manual

1. GENERAL DRAWING

Description and characteristics of the OTEF voltage Transformers

1- High voltage terminal

2- Insulation system (paper impregnated with oil)

3- Secondary terminal box

4- Oil level indicator

5- Metallic bellow

6- Insulator: porcelain or composite

7 – Aluminum tank

8- Feet with hole for anchoring

1

2

3

4

5

6

8

7

Instruction Manual

2. TRANSPORT, RECEPTION, UNPACKING

AND STORAGE

2.1. Transport

The VT shall be transported as indicated

by the manufacturer in an appropriate

packing. Depending on the limits of

transport heights, some of the VT can be

transported in vertical position. To

confirm this information on the packing

documentations.

Example of vertical packing

Example of horizontal packing

It is important to follow Factory

instructions regarding the stacking of the

packing in terms of transport and

storage when applicable.

ATENTION: The VT has fragile parts

(insulator, bellows top cover, etc.) that

can be damaged during transportation,

by sea, air or by road (being the road

paved or no). The transportation and

handling shall be made with care.

Sudden movements can cause impact

and damage to the equipment.

2.2. Reception

Whether the shipment is of

manufacturer’s or customer’s

responsibility, the customer inspector or

the service agent has to check the

following on receipt of delivery:

If the crates show any signals of impact,

blows or fractures, or if the transformers

have any signal of damage, or oil

leakage, the customer inspector or the

service agent in charge of receipt shall

make a written remark on shipment

documents. The receipt control, mainly

for the porcelain insulators and the

secondary terminal box, shall be done in

the presence of the forwarding agent, if

possible. The remarks regarding the

condition of the goods shall clearly state

details of the damages found at the time

of reception.

In case of damages, the customer

inspector in charge of receipt shall notify

GE and the insurance representative. All

contact information shall be indicated on

shipment insurance documents. This

declaration shall be made within

maximum of eight days after receipt of

the material.

Instruction Manual

2.3. Unpacking

Material required for unpacking, lifting

and put the transformer into service:

Qty Description

1 Crane, munck or hoist.

1 Contact grease type PENETROX or

equivalent.

1 Graphite grease MOLYKOTE type

P37 or equivalent.

4 Slings of 4,5m of length (capacity

10.000 N)

1 Sling of 1,5m of length (capacity

1.000 N)

Unpacking of the transformer should be

made with care.

 VT packed in vertical position:

1) Remove upper cover.

2) Remove the smaller extremities.

3) Remove the wood blocking pieces.

4) Remove the larger extremities

5)Remove the four screws at the

equipment feet.

6) Lift the VT

Example of wood blocking pieces

Example of lfting a VT

NEVER lift a transformer by its

primary terminal. Always lift it by

the four lifting holes on the

bottom tank.

VT packed in horizontal position:

1) Remove upper cover.

2) Remove the four screws at the

equipment feet.

3) Remove the smaller extremities.

4) Remove the larger extremities

5) Remove the green nylon slings pieces

Instruction Manual

6) Remove the VT from the packing and

lift it following the next steps:

 Use two slings, one at the neck of

the insulator and other at the hole

for lifting

 Remove the VT keeping it in

horizontal position.

 Gradually put the VT in vertical

position by lifting the sling

positioned in the neck of the

insulator. Always keep the sling in

vertical position. Handle with care

in order do not damage the top

cover.

 After confirming that the VT is in

vertical position and supported in

the ground, change the lift system

by four slings positioned at the four

lifting holes located in the bottom

tank. Also use the 1,5m sling to

connect the other ones near the

area of the neck of the insulator to

guarantee that the VT will not move

horizontally when lifting.

VT handled with its package:

To lift the packaged transformer with

crane or munck follow the marks on the

wood crate, once it indicates the right

position for the slings (nylon belts

reinforced) and avoid blows and

vibrations. Handle with care

Instruction Manual

Example of lifting the VT on its packing

2.4. Storage

- The transformers can be stored in

vertical position in homogeneous

surface. Every time that storage is

outside, remove the bellows blocking

system used for transportation only as

shown in 6.0 below.

NOTE: Always fix the transformer to the

ground even the stored is forecasted for

a short period of time.

- It is not allowed to store the VT in

horizontal position.

3. ANCHORING

The transformer should be set up in vertical

position. It is very important that the surface

on which the VT will be set up is flat

(tolerance no more than 1mm). Verify if the

four feet are supported on the structure. If

not, it is necessary to insert a shim before

putting the fixation screws.

4. CONTACT SURFACES PREPARATION

It is recommended to clean all aluminum

contact surfaces with sandpaper 150 grain to

eliminate the oxidation layer. Scrub the

contact surfaces with a metallic brush

(diameter of the thread 0,3mm) and

impregnate with grease of the type

“PENETROX” or equivalent. All the surfaces

must be completely covered with grease.

For silver or tinned contacts, only clean (do

not use sandpaper) and polish the side of the

aluminum. Cleaning silver or tinned surfaces

with sandpaper could cause damage to the

protection layer.

5. CONECCTIONS

5.1. Primary terminal

Connect the high voltage cable, or

tube, to the primary terminal with an

appropriate connector, so that they

assure a good contact. Be sure that

the instructions of the item 4.0 is

followed.

To fix the connect to the high voltage

terminal use a M12 screw applying

5,0 kgf.m (50 N.m) of tightening

torque.

Remark: The screw thread shall be

covered with graphite grease

MOLYKOTE type P37 or equivalent. Do

not use this Grease in the contact

surface.

5.2. Secondary terminals

For this connection, it is important to

have the set of drawings for this

equipment to confirm the type of

secondary terminals and the cables

accepted.

Use proper connectors to guarantee a

good connection. Tightening torque is

indicated in the drawing of the

secondary terminal box.

Instruction Manual

The neutral point of each secondary

shall be connected ti the grounding

terminal located in the terminal block,

in order to have a reference for the

voltage.

Secondary terminals not used must

be kept opened and a point be

grounded.

Never short circuit secondary

terminals of a VT. I can cause damage

and fail to the VT.

5.3. Terminal marking

Primary and secondary terminal

marking are done according to the

specified standard. See set of

approved drawings.

Primary and secondary connection

scheme are shown on the name plate,

fixed on the VT secondary box cover.

5.4. Grounding

The transformer tank has two

earthing terminals located at the

bottom tank that should be linked to

the substation ground system through

an appropriated grounding connector,

if requested, supplied with the

equipment. See set of drawings to

confirm rage of cable that can be

used.

Example of grounding terminal

Example of grounding connector

6. BELLOWS BLOCKING SYSTEM FOR

TRANSPORTATION

For transportation purposes, the bellows is

fixed (no movement) using a KIT of synthetic

cushion lightly compressed by the top cover

as shown in the picture below:

Example of bellows blocking system

Before putting the VT in the pedestal or

when storing, first it is necessary to remove

the bellows blocking system for

transportation following the steps below:

•Mark a reference line for the top cover

relative to the primary terminal (using a

marker or a pencil or any similar device) with

the aim of at the end of the procedure the

top cover Will be at the original position.

•Remove the four M6 screws that fix the top

cover to the bellows flange.

•Remove the top cover, with care, keeping a

vertical movement. Do with care in order do

Instruction Manual

not damage the bellows.

•Remove the bellows blocking system (kit of

synthetic cushion).

•Confirm by visual inspection that the

bellows are in good condition.

Geometry:

- The bellows cover in at horizontal: it is not

tilted by a possible deformation in the

bellows.

- The bellows is neither distorted nor

asymmetric: the convolutions are equally

distributed around the bellows

circumference.

Surface:

- There is no damage or deformation like

those caused by blows.

•Confirmed that the bellows is in good

condition, put the top cover in the original

position.

•Tight the four M6 screws with torque of

2kgf.m.

In case bellows show any type of

deformation or blow the VT should not be

put into service unless there is a formal

release from GE. In case of doubts, to contact

the technical assistance support of GE for

further information.

7. OIL LEVEL INDICATOR

The position of the oil level indicator can be

verified through the window of the top

cover. The plate of the indicator is divided in

three areas. Central green area shows the

normal operation condition and higher and

lower areas are shown with a red strip. In

normal conditions, the indicator shows the

central green area.

In case of oil level indicator is in either of the

red areas, the VT shall be taken off from

operation and GE informed immediately.

Example of oil level indicator

8. INSPECTION BEFORE FIRST ENERGIZING

•Confirm terminals connections to assure the

correct tightening torque.

•Confirm that there are no short-circuited

secondary terminals. If so they must be

opened and earthed.

•Confirm the ground connections of

transformer tank.

•Confirm that the oil level indicator is in the

central green area.

The VT are routine tested in the factory and

do not require repeated electric test. Look

for Project routine test reports for more

details.

Whilst al care is taken in the factory during

oil filling, the surface near of screws and

bellows could have a small quantity of oil.

This should not be considered as an oil

leakage provided that the bellows are

positioned within the green strip area.

It is not necessary to remove oil samples for

analysis. The VT is hermetically sealed.

If required, small quantity of oil can be taken.

Always verify oil level indicator before take

oil samples.

Instruction Manual

Never complete oil volume without prior

formal authorization of GE.

Important remark: During commissioning, it

is recommended to register the values

founded for each of the performed test to

compare with future measurements during

the VT lifetime. The measurements taken in

the factory are important and also the

measurements during commissioning of each

VT. Comparison between test results makes

sense to the field measured once it is

possible to follow the evolution of each

parameter.

9. MAINTAINENCE AFTER ENERGIZING

After installation and energizing, the VT

should not require any further intervention.

However, it is suggested to perform a visual

inspection during the first weeks of service

to:

•Confirm the position of oil level indicator. If

the indicator is significantly below or above

the central green area, in comparison with

other VT, it is recommend to check that there

is no oil leakage and, if an oil leakage is

discovered remove the VT from operation

and inform GE.

•With an infrared device, check if

connections are not overheating. Compare

with other VT from the same circuit.

After one year of operation, it is

recommended a detailed inspection of

tightening torques and oil leakage and

thereafter twice per year according to the

substation maintenance contract.

If posible GE suggests disconnecting the VT

and to perform the following examination:

•Insulator: Depending on the pollution level

it is necessary to clean the porcelain.

•Metallic components: check for corrosions.

•Tightening torque of primary and secondary

connections. Any adjustments should be

carried out.

•Secondary terminal box: If necessary clean

inside the terminal box.

•Confirm oil level indicator and if there is oil

leakage.

•Remove top cover to have access to the

bellows and confirm if there is an oil leakage

near the fixation of the bellows and / or if the

bellows is in good condition (no

deformations

10. TESTS AT SITE

The following test could be performed during

VT lifetime according to the best practice of

the user:

a) Voltage ratio (T.T. R)

b) Polarity (Polarimeter)

c) Winding resistance (Wheatstone

bridge).

e) Insulation resistance (Megger)

f) Infrared measurement.

11. FINAL DISPOSAL OF THE TRANSFORMER

PARTS AFTER LIFETIME

The high voltage instruments transformers

are made of the following components,

which after life time require a properly

disposal to prevent environmental

contamination:

Instruction Manual

Components Recommended

Disposal

Metallic materials Metal recycling

company

Resin and materials

saturated with resin

Industrial landfill,

properly licensed by the

state’s responsible

agency.

Oil (PCB-free) –

classified as Class I

hazardous residue

Oil refinery at a

company which is

properly licensed to

perform such an

activity

Material contaminated

with oil

Co-processing or

incineration at a

company which is

properly licensed by the

state’s responsible

agency.

Porcelain insulator Industrial landfill,

properly licensed by the

state’s responsible

agency

Other materials Industrial landfill,

properly licensed by the

state’s responsible

agency

The disposal of oil and components

contaminated with oil directly into the soil or

water is prohibited.

For further information or clarifications,

contact GE environment department:

+55 35 36297112.

GE OTEF-72 User manual

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