2. Contents
• Introduction
• Basic Arrangement of TG in Industries
• Parts of Turbo Generator
• Excitation System
• Testing of Turbo Generator
• Cooling System of Turbo Generator
• Conclusion
3. Introduction
• What is a TURBO GENERATOR ?
• Principle of Electrical Generator
• Basic Arrangement of TURBO
GENERATOR in industries
Generator
Turbine
Exciter
4. Constituents of Turbo Generator
• Stator Frame
• Stator Core
• Stator Winding
• Overhang Base
• Rotor
5. TG Stator Core
• 500 MW Stator Core
Made by Spiral Stacking
Made of CRGO Si Steel Stampings.
Advantage of Spiral Stacking- Better Locking
500 MW TG Core Bar
Used for locking of
stampings
Made of Mild Steel or
Stainless Steel
Wedge Teeth
Winding Slot
Holes for
Cooling
Holes for
Studs
Core Bar
Slot
6. TG Stator Winding
Double Layer Winding is Used
Double Layer Winding Concept
Stator Bars
Winding in Stator Core
Manufacturer Data for 500MW TG Stator
Mechanical Specifications
• No of Slots : 48
• No. of Core Bars : 24
• Stator bars numbering:
[1-48 : Lower Stator Bars
51-98 : Upper Stator Bars]
• No. of Baskets : 6
Electrical Specifications
• Terminal Voltage = 21kV
• Rated Current = 28000 A
• Rated P.F. = 0.85 Lagging
• Efficiency = 99.75%
7. TG Rotor Core and Winding
• Rotor has Concentric Winding.
• 500 MW rotor is made of 2 Poles.
• Rotor Winding bars are placed and
connected in Rotor slots in a opposite
manner (one CW and other ACW)
• Opposite pole windings are connected
using Z conductor
Manufacturer Data for Rotor
V = 400 V ; I = 6000 A
8. DC Excitation System
Diode Wheel/Rectifier Wheel on Exciter
Schematic of Brushless Exciter
• Automatic Voltage Regulator (AVR)
• Permanent Magnet Pilot Exciter
• Measuring Slipring with Brushes for Field
• Quadrature axis Measuring Coil
• Three Phase Main Exciter
• Diode Rectifier Set
• Three Phase Lead
• Multicontact Connector
• Rotor Winding of TG
• Stator Winding of TG
Manufacturer Data for Exciter
V = 400 V ; I = 6000 A
9. Testing of Turbo Generator
• Winding Resistance:
[Resistance Measurement of Stator winding, Exciter Stator
and Exciter Rotor Winding using RTD.]
• Insulation Resistance: [Performed before and after HV Test]
[use Meggar to measure IR of Winding w.r.t. earth]
[apply Meggar Voltage for 60 seconds and 600 seconds]
[Calculate PI(Polarization Index) = IR(600 sec)/IR(60 sec)]
PI should be > 2.0 [Lower values of PI indicate bad insulation resistance of machine]
• High Voltage Test:
[use formula : V = (2Vn + 1)kV ; Vn = rated voltage of Generator & V = Applied High Voltage]
[Apply High Voltage between each phase and ground; connect other phases to ground]
[Duration for High Voltage Applying = 1 Minute]
10. Testing of Turbo Generator Continued…
• Mechanical Heat Run Test:
[RTD, Bearing, Body and Ambient
Temperatures are recorded at equal
intervals till thermal equilibrium is
achieved, then Machine is stopped & Hot
resistance of winding is also measured]
[Over Speed Test : Machine is run at 120%
rated speed for 2 Minutes]
[500 MW TG Test Bed at BHEL, Haridwar, BLK-I]
11. • Open Circuit Heat Run Test:
[ Machine is run at rated speed and rated voltage. ]
[Power input to Prime Mover, Generator Voltage, Exciter voltage and Current, RTD, Bearing, Body
and Ambient Temperatures are recorded at equal intervals till thermal equilibrium is achieved, then
Machine is stopped & Hot resistance of winding is also measured]
[Sine wave of 3-Phase Voltage is recorded by C.R.O.]
[Phase sequence is tested by using phase sequence indicator]
[All the three phases are checked for balance]
[Noise Level Test: Noise level is measured from different locations of machine and background
noise level is also measured after stopping the machine and actual noise level of machine is
calculated]
[Shaft Voltage measurement: measure using multimeter between D.E. and N.D.E. of Shaft]
[Vibrations Measurement: Vibrations at Horizontal, Vertical, Axial directions at both D.E and N.D.E
are measured using Piezo Electric Sensors]
Testing of Turbo Generator Continued…
12. Testing of Turbo Generator Continued…
• Short Circuit Heat Run Test:
[ Machine terminals are shorted and machine is run at rated speed and rated
current. ]
[Power input to Prime Mover, Generator Current, Exciter voltage and Current,
RTD, Bearing, Body and Ambient Temperatures are recorded at equal intervals
till thermal equilibrium is achieved, then Machine is stopped & Hot resistance of
winding is also measured]
[Momentary overload Test: Machine is excited to 150% of rated current for 30
Seconds]
• Impedance Test of Rotor:
[A 1-ϕ variable voltage is applied to field winding and currents at 25%, 50%,
75% and 100% voltage are measured]
13. Cooling System of Turbo Generator
• Hydrogen Cooling is used for Core and Body
• Water Cooling is used for Windings (Distilled Water is used)
Process:
1. Dry air pressure is given to machine using Si
Gel.
2. CO2 Pressure is given to remove air from
machine (Air removed).
3. N2 Pressure is used to take the machine
temperature down. (CO2 removed).
4. Hydrogen Pressure is given to the machine
and maintained.
5. Hydrogen is sucked at high pressure and sent
to chiller which cools the Hydrogen.
Chiller
14. Conclusion
Experience in Bharat Heavy Electricals Ltd, Haridwar being a Vocational Trainee was very
interesting and inspiring. Though 45 days duration is very little to explore even a single
block of the plant, yet I have tried to learn as much as I could. I got to know about the
industrial equipment which are generally used in an industry.
Besides Technical Knowledge, I also observed management system of plant and working
environment and being one of the leading manufacturing companies of industrial products
B.H.E.L. has very inspiring and positive working environment. This company has very
talented personnel who answered me everything what I asked. This company is doing very
good to improve Power System Efficiency and Power Quality and Safety.
