STEAM TURBINE

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Technical Data, pictures and section drawings - MAA

Lube Oil System - MAV

Control Oil System - MAX

Gland Steam System - MAW

Turbine Drain System – MAL

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TSE and Margins

STG Start Up and Shut Down

STG controller

Detailed discussion on Protections

Lub Oil Purification Unit

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2 to 3: Isobaric heat rejection (Condenser)

3 to 4: Isentropic compression (Pump)

4 to 1: Isobaric heat supply (Boiler)

1 to 2: Isentropic expansion (Steam turbine )

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Steam Parameter Limits

Steam Flow – 325.44 kg/s

Steam Pressures in Bar Absolute

Nominal Long Term Short Term

Main Steam 76.5 85.7 99.5*

Before 1st Stage 75.5 81.5 81.5

Exhaust Steam 2.23 5.0 7.0

Long Term – Upper limit with no time restriction

Short Term – Permissible instantaneous value with cumulative

duration not more than 12 hours in a year.

* - Set the safety valve so as not to exceed this value

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Turbine Oil Specs

Mineral or Synthetic oil of viscosity class ISO VG 32 or ISO VG 46 (DIN 51 519)

Capable of withstanding 120 ºC in bearings and 80 ºC in the oil tank without physical or chemical degradation.

Hydraulic Oil – ISO-L-HM46 (DIN 51524-HLP46) capable of withstanding 70 ºC.

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Hydro Safe ISO VG 32

Non-Toxic - Biodegradable - Environmentally Friendly Antiwear - Hydraulic Oil

Hydro Safe ISO VG 32 is a vegetable based hydraulic fluid formulated to meet the demand for biodegradable hydraulic oils. It is designed to minimize environmental impact and have low environmental persistance. Hydro Safe ISO VG 32 offers excellent antiwear performance in a wide array of hydraulic components, and can be used as a superior replacement for conventional petroleum oil. It exhibits good thermal and oxidative properties when compared to other vegetable-derived products. Formulated from canola oil, and containing biodegradable, non-toxic chemical additives. Its high vicosity index (VI) allows outdoor operations in winter and summer without the need for fluid changes or equipment modifications.

Viscosity Index ASTM D-567, ASA Z11.45 is an empirical number indicating the rate of change in viscosity of an oil within a given temperature range. A low viscosity index signifies a relatively large change in viscosity with temperature change, while a high viscosity index shows a relatively small change in vicosity with temperature change. Viscosity Index cannot be used to measure any other quality of an oil.

The fluid is totally biodegradable, and exceeds the government criteria of being "readily biodegradable." Readily biodegradable is defined as an attribute of products that have a natural ability to biodgrade quickly and completely. Once the fluid is leaked into the ground, it has the ability of substance to be digested or consumed by naturally occurring microorganisms present in water, air, and soil systems. Complete biodegradability is the conversion of a substance to carbon dioxide and water.

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Steam Purity – Why ?

Impurities can cause damage to turbine components by - corrosion, stress corrosion, corrosion fatigue, erosion-corrosion.

Deposition can cause - thermodynamic losses, lower efficiency, upsetting of pressure distributions, clogging of seals and clearances

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Values recommended for continuous

operation

Parameter Unit Normal Value Achievable

Value

ACC @ 25 ºC μS/cm < 0.2 0.1

Na μg/kg < 5 2

Silica μg/kg < 10 5

Total Iron μg/kg < 20 5

Total Copper μg/kg < 2 1

Mass weighted averaging for multiple sources. i.e. if A – conductivity

A = ∑Mi * Ai / ∑Mi

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Limit Values for Start Up and cases of

deviation from values recommended

for continuous operation. Parameter Unit

Action Level 1

Action Level 2

Action Level 3

Action Level 4

ACC @ 25 ºC μS/cm ≥ 0.2 < 0.35 ≥ 0.35 < 0. 5 ≥ 0.5 < 1.0 ≥ 1.0

Na μg/kg ≥ 5 < 10 ≥ 10 < 15 ≥ 15 < 20 ≥ 20

Silica μg/kg ≥ 10 < 20 ≥ 20 < 40 ≥ 40 < 50 ≥ 50

Total Iron μg/kg ≥ 20 < 30 ≥ 30 < 40 ≥ 40 < 50 ≥ 50

Total Copper μg/kg ≥ 2 < 5 ≥ 5 < 8 ≥ 8 < 10 ≥ 10

Hours per event allowable

h ≤ 100 ≤ 24 ≤ 4 0

Cumulative time per year

h/a ≤ 2000 ≤ 500 ≤ 80 0

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Output Limit During Valve Testing

While testing the Main Steam Stop and Control Valves with Automatic Turbine Tester, the Turbine output should be limited to 80%

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Turbine Stop & Control Valves

2 Stop and Control Valves each

Stop and CV combined in a common body with stems arranged at right angles

Stop Valve – Single seat valve with integral pilot disk. Hydraulic actuation against spring force – will close in case of power failure to solenoid

CV – Tubular disk with relieving holes. Hydraulic actuation against spring force.

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Function – ESV – MAA11/12AA051

Rapid and reliable interruption of Steam Supply to the turbine in case of activation of protection.

To allow admission of steam for warm up of the CV during cold start

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Function – CV – MAA12/22AA151

Rapid interruption of Steam Supply to the turbine in case of activation of protection

Allow admission of steam into turbine for warm up during start.

Control the speed gradient during run up to Nominal speed

Control the load of the steam turbine when synchronised

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Example

(Not at

S1)

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ST ESV

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ST CV

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TURBINE EXHAUST

AND SAFETY

VALVES

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Lube Oil System - MAV

Safe Oil Supply to Bearings

Jacking up shaft at low speeds

Driving the hydraulic turning device

Avoid escape of oil vapours from the bearings and the oil tank

Oil cooling

Oil Purification

Special Op mode during Fire Protn

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Main Components Lub Oil Tank MAV10BB001 2 x 100% LOPs (~ 5.5 Bar) MAV21AP021/022

1 x 100% EOP (~ 2.5 Bar) MAV24AP001 2 x 100% Lift Oil Pps (~ 160 Bar) MAV24AP001

2 x 100% Vapour Extractor fans MAV82AN001/2

2 x 100% Lub Oil Coolers

2 x 100% Lub Oil Filters

Thermostatic Temperature CV

Oil Purification Unit

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Thrust Pads

Journal Bearing

Manual Turning Gear Mechanism

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Control Fluid System MAX

Supply the ST ESVs, CVs and Safety Valve actuators with high pressure control fluid (160 Bar)

Fast closing/opening of valves when Trip signal actuated.

Transmission of electrical signals from turbine controller into hydraulic signals for fast and accurate positioning of CVs

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Main Components

Control fluid tank MAX01BB001

2 x 100% control fluid pps MAX01AP001/002

2 Hydraulic accumulators MAX01BB011/012

2 filters downstream of each pump MAX01AT011/012

1 Circulating oil pump MAX01AP011

1 Control fluid cooler MAX01AC011

Fine mesh filter d/s of cooler MAX01AT013

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Gland Steam

Extraction Points