PFIFFNER Deutschland GmbH · Density Monitor Testing Device ... Extremly space saving. ... The labor costs for manufacturing a gas insulation are extremly low ...

PFIFFNER

Deutschland GmbH

Gas Insulated Transformers

Raimund Streland

CEO Pfiffner Germany

Gasisolierte Messwandler NEU.pptx Streland erstellt 2017-05-09 / Seite 2 / 12.06.2017

SF6 = Sulphur Hexafluoride

- Non toxic

- Inert ( like a noble gas )

- High dielectric strength

- Thermal and chemical stability

- Long-term prooven and tested

Insulation Principle: Electronegativity

( System „Pacman“ )

THE GAS:

THE TRANSFORMER: OUTDOOR ( AIS )


EGF 245…550 kV

Tank Type Voltage Transformer

JGF 245…550 kV

Head Type Current Transformer

EJGF 245…550 kV

Combined Transformer

Transformer Types


Head Type Current Transformer


Primary Coil

Stacked Core

Seconrary Coil

Secondary Coil

Voltage Transformer Part ( Combined Transformer )


Voltage Transformer

Current Transformer

Current Transformers Support

Arrangement Combined

Transformer


Current Transformers Support

Primary Reconnection 2 Windings for max. 4000 A using Aluminum conductors


Head Housing for 1:2:4

Primary Reconnection 4 Windings


Principle Arrangement For The 1:2:4 Reconnection

Primary Conductors

Return Conductor


X-Ray Tank Type Voltage

Transformer EGF 420


20°C 70°C

Rated Pressure PD =

Designpressure

Routine Test

Pressure

2 x PD

Bursting Pressure

5 x PD ( Type Test )

Rated Pressure

Bursting Disc

Pressure Coordination

Routine Test ( EACH PART )

Bursting Test ( Type-Test )

Rated Pressure Of The Bursting Disc


Pressure Relief: Metallic-Bursting Disk, Rated Pressure Pe=10 bar

No installation flaws by forced centering of the disc and the flange


Standard:

Density Monitor

Temperature Compensated

Pressure Gauge

Conventionally with display

as shown – or fully electronic

Two pairs of signal contacts

for the pressure alarm

signal


Density Monitor Testing Device

Dismantling the density monitor for

testing is not required by using the

test device


Insolation systems

Oil Paper Insulation

PRINZIPLE: Barrier

- The oil paper insulation is a layer

insulation, produced in "manual

work".

- Self-supporting.

- Active part is a complete self

contained system.

- Drying and impregnation

processes must be carefully

executed.

Gas Insolation

PRINZIPLE: „Pacmen“

- The inner surfaces of the housing,

the core shields of voltage

transformers, the core housing

and the primary conductor are

electrode surfaces. These have

to be accordingly smooth and

need sufficient radii.

- Not self-supporting Support

insulators required.

- Internal winding solutions are NOT

possible.

- Pressure relief works reliably

( gas is compressible ).

- Temperature-dependent

( liquefaction at low temperature ).



THE TRANSFORMER: GIS ( MAINLY INDOOR )

GIS = Gas Insulated Switchgear


[email protected] / Seite 19 / 12.06.2017

The GIS-market ist increasing

- Land is becoming increasingly expensive, so it´s a big advantage to

put the whole switchgear in a relatively small house.

- A whole bay can be delivered completely assembled in a container.

- The staff has access to the switchgear under power.

- The cores of the current transformer are located on the „low voltage

side“. Some GIS manufacturer put the cores outside the

encapsulation.

Voltage Transformer Three Phase Unit


Voltage Transformer

For GIS voltage transformers a special

testing equipment is required


Gas Insulation advantages


- No hand crafting of the insulation, easy construction, high reproducibility.

- Explosion proof due to the pressure relief.

- Combined units für voltage ratios > 300 kV are easily possible

- Advantage GIS: Extremly space saving.

- No ageing of the insulation.

Just connect the filling device to the transformer

and open the valve Gas insolation = Insolation from the bottle

The labor costs for manufacturing a gas insulation are extremly low …


Gas Insulation disadvantages


- Particle sensitive. This is the biggest disadvantage for the

manufacturer.


Gas Insulation disadvantages

- No ageing of the insulation. SF6 has an extreme chemical stability.

This leads to a GWP ( Global Warming Potential ) of 20 000. This

means, that 1 kg SF6 has an aequivalent of 20 tons of CO2.

- This may be relativated in the future by using one of the new

„replacement“ gases for SF6. But these are not really prooven and it

is actually not clear, witch of these gases will be used as „standard“.

- Gas insulated transformers are pressure vessels. Routine testing

required, lots of certificates have to be collected and stored.

- Density monitor required.

- Internal primary windings, as used in oil insulated transformers, are not

possible, so max. number of primary windings is 4.

Partikeles =

Public Enemy

No. 1

- Accumulate at areas of high field strength.

- Particles lead to failures in the final test.

- Flashover will happen WITHOUT any

warning ( e.g. warning by PD )

- Can also accrue after the test ( e.g. due to

transport vibration )

- Can cause operating failures

- Also insulating parts can be covered by

particles


[email protected] / Seite 27 / 12.06.2017

PLEASE NOTE:

Often people speak about „consumption“ of SF6 gas

in regards of insulating switchgear.

This is not true = FAKE NEWS

The SF6 gas is not burned or consumed in the

transformer.

It is „stored“ while doing it´s job.

After the livetime of the transformer it can be win

back to start a new live in a new transformer.

OK, thats it..

Thanks for your attention and

patience


PFIFFNER Deutschland GmbH · Density Monitor Testing Device ... Extremly space saving. ... The labor costs for manufacturing a gas insulation are extremly low ...

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