Industrial Gas Turbine

Unit 304 – Starting Equipment

Topic ‘D’:

4.1 – Types of Starting Devices.

4.3 – Starting sequence of Gas Turbine.

Aim & Objective

Aim:

To demonstrate knowledge of the function of

Starting Device for Industrial Gas Turbine.

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Aim & Objective

Objective:

At the end of this lesson, you should be able

to:

•Describe the different types of starting

device of a Gas Turbine.

•Explain the sequence from initial starting

until turbine reaches self sustaining speed.

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4.1 – Type of Starting Devices

Purpose of Starting Devices?

- To crank the turbine engine for start-up.

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Function of Starting Devices:

1. Supply high torque at zero speed.

2. Drive the unfired gas turbine to an

acceptable firing speed.

3. To assist the fired turbine to a self-

sustaining speed.

4.1 – Type of Starting Devices

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The devices used to start Gas Turbine are:

1. AC Electric Motor. (operation)

2. Diesel Engine. (operation)

3. Steam or Expansion turbine. (operation)

4. Pneumatic starter. (operation)

4.4 – Starting sequence of Gas Turbine

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Start Switch

Pushed

Auxiliary Lube

Oil Pump Run

Pressure > 6 Psig

Auxiliary Seal

Oil Pump RunDifferential

Pressure

16 – 20 psig

Purging

CompressorLoading v/v open

(30 sec)

Pressurizing

Compressor

Vent v/v closed

Starter Motor/

Diesel start to

Crank Engine/

Gas Turbine

Pre-Lube Oil

Pump Fail or

Pressure

Gauge Faillure

Aux Seal p/p

Failed or Diff.

Press. Gauge

Failed

Starter Devise

Failed

Fuel Pump

Failed(No Fuel Admitted)

Fuel System

Activated(Fuel Delivery

Pump Run)

Failure in

Ignition

Spark Plug

Ignite(3 – 10

discharge/sec)

Starter Motor/

Diesel Starter

Disengaged

Turbine Speed

5% - 20% of

Rated Engine

Speed(Light Off Window)

Engine Speed

Reached a

Self-Sustaining

Speed(Engine Temp

Increased >

350°F)

*Eng Driven

L.O. Pump

Press reached

35 psig.

*Fuel Press

> 35 psig.

*Eng Temp

reached 800°F

Ignitor & Aux

L.O PumP

Shut Off

Turbine Speed

Increased to

60% - 62%

Ideal Speed(20,000 R.P.M)

Turn Engine

Speed Control

Knob

Clockwise to

Selected

Engine Speed(Engine Speed

Increasing > 90%)

Starter System

Deactivated

Auxiliary Seal

Oil Pump Shut

Off

Compressor is

now Online(Ready to Take

Load)

Engine Failed

to Start(Low Pressure

Fuel)

Engine Failed

to Load

4 Minutes Interval

7 M

inu

tes

Inte

rva

l

No

Yes Yes Yes Yes Yes Yes

Yes10

Sec

Yes

10

Sec

YesYes

Yes

YesYes

2

Min

No No No

No

NoNo

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4.4 – Starting sequence of Gas Turbine

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Check during Operation:

• Check for unusual condition.

• Check for vibration & Noise.

• Check for any changes in accelerating

time.

• Check exhaust temperature.

• Check oil level for leak.

• Check battery charger.

Recap

•Describe the different types of

starting device of a Gas Turbine.

•Explain the sequence from initial

starting until turbine reaches self

sustaining speed.

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√

√

Overview

Overview of next week lesson:

Topic 4.2 – Torque Converter

Topic 4.3 – Hydraulic Ratchet System

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Thank you for your Attention

4.1 – Type of Starting Devices

• Main Starter.

• Utilizes electric current to run the motor.

• Turn the turbine through gear box

arrangement.

• Self-releasing mechanism engage once

turbine run on self-sustaining speed.

• Required special insulation. (Intrinsically

safe)

AC Electric Motor

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4.1 – Type of Starting Devices

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Alternating Current Electric Motor

4.1 – Type of Starting Devices

• Secondary starter.

• Started by Hydraulic pressure.

• Release hydraulic fluid to the starter

motor to crank the engine.

• Engage clutch mechanism to run Gas

Turbine.

• Generate power supply for its own

control panel.

Diesel Engine

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4.1 – Type of Starting Devices

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Lister Type

Diesel Engine

4.1 – Type of Starting Devices

•Utilized high pressure and temperature

steam.

•High velocity steam directed to the rotor

blade.

•Connected to Gas Turbine shaft.

•Required separate boiler.

Expansion turbine

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4.1 – Type of Starting Devices

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Expansion Turbine

4.1 – Type of Starting Devices

•Utilize Compressed air/High pressure gas.

•Use Vane type starter motor fitted on the

Forward side Accessory gear.

•Starting torque transmitted through

running gear arrangement via clutch and

shaft.

•Required pneumatic power supply. (At

pressure of 1138kPa – 1379kPa for

60Sec – 90Sec at a rate of 67m³/min)

Pneumatic starter

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4.1 – Type of Starting Devices

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Gas Turbine Air Starter

Intrinsic Safe (IS)

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Term

• A special insulation protection technique

for safe operation of electronic equipment

in explosive atmospheres.

• To ensure that the available electrical and

thermal energy in the system is always

low enough so prevent ignition on the

hazardous area.