seminar on power former

7/29/2019 Seminar on power former

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Seminar on

Power former- ABreakthrough of high

voltage generators.

By Nazneen kousar.

Guided by: Asst. prof. Arathi P.B


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Contents-

Objective. Function.

Cable construction.

New design. Field distribution.

Abnormal situations.

Cooling ways. Comparison.

Merits and de-merits.

Applications.


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Objective :

To introduce a device which providesdirect connection to power grid with-out an intervening step-up transformer.


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What is power former ?

Generator transformer power former

Power former is same as generator the only

difference being in its construction.


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Pictorial representation-

1.Generator

2.Generator circuit

breaker

3.Surge arrestor

4.Transformer

5. Circuit breaker


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Cable construction-

1. Cable strands.

2. Inner-semiconducting

layer.

3. Solid Insulation.

4. Outer-semiconductinglayer.


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Stator design-

(a) 1-rotar, 2-section of stator, 3-teeth,

4-slots, 5-main winding cable, 6-auxillary

winding.


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(Stator design cntd.)

Stator slot teeth arebroader.

Slots consists ofcylindrical bores

arranged radially.

Each winding requiresless cable insulation

Winding features highvoltage and low current.


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Field distribution-

Circular

conductors have

uniform field

distribution.

Output power is

increased in-turn.


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Features of XLPE cables-

Cross-linked polyethylene, orXLPE, is a

form of polyethylene with cross-links.

higher conductor rating of 90 degreeC.

Have greator continuos and short

circuit current capacity.

"Super Clean Material Supplying

System."
http://en.wikipedia.org/wiki/Polyethylenehttp://en.wikipedia.org/wiki/Cross-linkhttp://en.wikipedia.org/wiki/Cross-linkhttp://en.wikipedia.org/wiki/Cross-linkhttp://en.wikipedia.org/wiki/Cross-linkhttp://en.wikipedia.org/wiki/Polyethylene


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Cooling system-

Cooling done at zero potential.

Tap water can be used.

XLPE pipes used axially.

No radial duct.

Less risk of short circuit.


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During abnormal conditions -

Two or three phase

faults occuring are

much lower.

Single phase faults are

of low magnitude

compared toconventional

generators.


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Comparison with

conventional system

Improved over-loading capabilitycomparingly.

More reative power output.

Highly compact insulated cabling.

Possesing less components.


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Differential protection-

Winding cables can be considered as

capacitor.

The machine adopts graded insulation.

Use of self- adaptive compensation

methodology.


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Merits-

High energy efficiency.

Comparingly Much reliable.

Continous operation.

Low operating temperatures.

Lower environmental impact.


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De-merits-

Large volume required.

Much expensive.


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Applications-

A turbo generator with rated voltage of

136kv and a capacity of 40MVA.

Hydro generator with rated voltage of 155kvand a capacity of 75MVA.

Another Hydro generator with rated voltageof 78 kV and 25 MVA rating.


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Use of XLPE cable in hydro power

former


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Cable being threaded through thebores in porjus stator.


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Conclusion-

Revolutionizing an century old power

generation convention.

A long term development plan calls forpower former with rated voltage of 500kv.


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References -

M.Leijon,L.Gertmar, breaking conventions inelectrical power plant.

M.Leijon, Power former- A radically new rotating

machine.

Q.Tian, X.Lin, and P.Liu, A novel self adaptivecompensation method.

F.Owman and T.Karlsson Power former:A Giantstep in power plant engineering.


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queries??????


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Thank you

seminar on power former

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