Seal Oil System T

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Powerpoint Templates

210 MW LMW

GENERATOR

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Page 2 Powerpoint Templates

Generator

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Need of Sealing -

 In Hydrogen Cooled Generator .

Where ?

 To Prevent escape of Hydrogen from

Generator casing along the rotor shaft.

Why ?

How ?

 By Providing radial and axial oil film.

 Oil pressure = higher than hydrogen gas.

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1) Thrust type seals (LMW)

2) Ring type seals (KWU)

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 Oil supply to seals through an injector in normal

operation.

 Automatic taking over of oil supply by pumps.

(A.C. and D.C.)

 Cools and filters the oil before supplying to seals.

 Always maintain a constant differential pressure

between the seal oil pressure and hydrogen

pressure at varying casing pressure.

 Drain out effectively the oil flowing towards the

hydrogen side without allowing any hydrogen to

escape.

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IN ORDER TO PREVENT

THE ESCAPE OF HYDROGEN

FROM GENERATOR, SEALS

ARE USED ON EITHER

ENDS OF THE MACHINE

WHERE THE ROTOR COMES

OUT OF THE STATOR.

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• The shaft seal consists of seal liner with

• babbitted surface pressing against the

• collar of the rotor and is suitable mounted

• in a seal body so as to be able to follow

• the rotor free in the axial direction.

• Oil under pressure is supplied to an

• annular chamber in the seal body from

• where it is led to the space between the

• seal liner and rotor collar through several

• canals distributed uniformly along the

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• This oil under pressure and under the

• influence of rotation and configuration of

• the seal linar surface , forms a continuous

• hydrodynamic film between the collar and

• liner which prevents the escape of

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GENERATOR SEAL

• THE SHAFT SEAL CONSISTS OF ---

• 1) SEAL LINER

• 2) ROTOR COLLAR

• 3)SEAL BODY

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 Oil injector

– 1 no.

 Seal oil pump coupled to AC motor

– 1 no.

 Seal oil pump coupled to DC motor

– 1 no.

 Oil coolers - 2 X 100% capacity

 Mechanical filter

– 2 X 100 % capacity

 Differential Pressure Regulator - 1 no.

 Pressure Oil Regulator - 1 no.

 Damper tank - 1 no.

 Hydraulic seal oil tank - 1 no.

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Differential Pressure Regulator (DPR) -

To Damper Tank

Seal Oil Inlet

Seal Oil Press. Feedback Seal Oil Outlet

Sensing Line of Hydrogen Pressure

Bypass Vlalve

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From Damper Tank

Press Oil Regulator (POR) -

Inlet to POR Bypass Valve EE Feedback Line of Thrust Oil Outlet of POR TE

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Powerpoint Templates Page 16 Outlet H2 Feedback to DPR Drain from Exciter side Feedback connection between hyd. Seal & damper tank

Overflow from Damper tank

Hydraulic Seal oil tank-

Drain from turbine side MOT H2 press connection from casing

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Damper tank -

From DPR Outlet H2 Feedback Seal Oil to Shaft Seal Spill Over to hyd.

Seal oil tank Vent

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 H₂ pressure - 3.5 kg/cm2 (for 210 MW)  Seal Oil Pressure - 4.1 to 4.4 kg/cm2

 Seal Oil Temperature - 40 °C.

 Quantity of seal oil - 80 lit / min (For Seal)  Quantity of seal oil

flowing towards H2 side - 1 to 2 lit / min.  Pressure of Thrust Oil - 1.5 to 2.2 kg/cm2

 Qty of Seal Oil - 4000 lit. to fill the system

 Injector Outlet Pressure - 10 kg/cm2_.

 A.C. SOP start at - 6.5 kg/cm2_.

 D.C. SOP start at - 5.5 kg/cm2_.

 DPR - Inlet Press of oil - 10 to12 kg/cm2_.

 POR - Inlet Press of oil - 10 to12 kg/cm2_.

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AC SEAL OIL PUMP

SPECIFICATION OF PUMP

• TYPE: -MULTISTAGE, VERTICAL SPLIT

• CENTRIFUGAL PUMP

• DISCHARGE: --- 3.6 litre/sec

• HEAD: --120 M OF WATER COLUMN

• SPEED: --- 1465 RPM

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DC SEAL OIL PUMP

• SPECIFICATION OF PUMP

• TYPE: MULTISTAGE, VERTICAL SPLIT

• CENTRIFUGAL PUMP

• • DISCHARGE: --- 3.6 litre/sec

• HEAD: ----120 M W C

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SEAL OIL COOLER

• NO. OF COOLERS: --- TWO

• TYPE: DOUBLE PASS, VERTICAL

INLET OIL TEMP: -- --- 40

0 C

• OUTLET OIL TEMP: --- 50

0 _C

• INLET PRESS. --- 10 KG/CM

2

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• OIL FILTERS

• TYPE:--- WIRE MESH DISC TYPE

• MATERIAL OF FILTER: ---- BRASS

• PRESS. DROP :--- 0.4KG/CM2

• ACROSS FILTER

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DIFF. PRESS. REGULATOR

(DPR

)

• TYPE: --- PLUNGER TYPE

• INLET OIL PRESS.:--- 10-12 KG/CM

2

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THRUST OIL SEAL OIL

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MOT SEAL OIL HEADER

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Powerpoint Templates Page 26 DAMPER TANK DPR POR HYDRAULIC SEAL OIL TANK TO EXCITER END HEADER EXE. END TUR. END

LUB OIL OUTLET HDR

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 Seal Oil pressure low .

 Thrust Oil pressure low

 Differential Pressure between oil and hydrogen is low .  Differential Pressure between oil and hydrogen is high  Pressure of cooling water to seal oil coolers low

 Oil Level in damper tank too low

 Oil level in hydraulic seal oil tank low .  Oil level in hydraulic seal oil tank high .

 Pressure of cooling water to seal oil cooler low

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Seal oil pressure

Gas pressure inside generator casing Thrust oil pressure

Differential pressure between hydrogen and seal oil Presence of liquid inside the machine

Oil level in hydraulic seal Oil level in damper tank

Pressure drop across the filter

Pressure at the outlet of the injector or pumps

Cooling water temperature, pressure at inlet and outlet of coolers

Operational Checks -

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 Very little quantity of seal oil flows towards H₂ side thus making a lesser effect on H₂ purity during operation.

Advantages & Disadvantages -

Advantages -

 A separate collar has to be provided on the rotor shaft.

 Restricts the flexibility in rotor shaft expansions, rotor collar movement, is limited to the allowances available in the seal body.

 Excessive thrust on the seal ring or sudden impact of rotor may damage the babbit surface of the seal ring and it may require machining of the rotor collar also, due to mechanical rubbing between seal ring and rotor collar.

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