Water and Power Development Authority

(WAPDA)

Internship Report
Submitted to: Sir. Jahanzaib Khan
Submitted by: Uroosa Iftikhar
From: Namal University Mianwali
Department: Electrical Engineering(EE)

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Declaration Form
I, Uroosa Iftikhar , bearing Registration Number BSEE-2020-03 in the Electrical
Engineering program, have successfully concluded a six-week internship at the
Chashma Hydro Power Plant. Throughout this period, I was under the guidance of
Mr. Saeed Ur Rehman, who serves as the Executive Engineer for operations. He
can be reached via email at operationchp11@yahoo.com.

Heartfelt thanks to:

Mr.Humair Daniyal (AXEN Operation )
Mr.Faheem Javed (AXEN Electrical)
Jahanzaib Khan (Operations)

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Dedication/Acknowledgement (Optional)
"I want to express my sincere gratitude to the WAPDA team for their support and guidance
during my internship. Their collective expertise and collaborative spirit greatly contributed to my
learning experience. The practical experience gained was instrumental in my professional
development. Additionally, I would like to thank my family and friends for their unwavering
support."

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Contents
Introduction to Hydro-Electricity ..........................................................................7
Working of Hydro-Electricity: .............................................................................................................. 7
Generation of Hydro-Electricity: .......................................................................................................... 8
Hydro-Electricity generation in the World vs. Pakistan ..................................................................... 9
Chashma Hydropower Station .............................................................................10
Important Facts about Chashma Hydropower Station ..................................................................... 11
Effect on Environment ......................................................................................................................... 13
Operational Section................................................................................................14
Kaplan turbine: ..................................................................................................................................... 14
Turbine Control panel .......................................................................................................................... 16
Excitation Mechanism in Power Plants .............................................................................................. 18
Voltage and Frequency Control in Turbines ...................................................................................... 20
Operational Specifications: .................................................................................................................. 20
Electrical Section ....................................................................................................21
Transformer .......................................................................................................................................... 21
Step-up transformer: ........................................................................................................................ 21
Axillary Transformer: ...................................................................................................................... 23
Generator and Alternator .................................................................................................................... 24
Main Generator: ............................................................................................................................... 24
Exciter Generator: ............................................................................................................................ 25
Coordination: .................................................................................................................................... 25
Voltage and Frequency Control: ..................................................................................................... 25
Generator control panel: ...................................................................................................................... 26
Switchgear and Circuit breaker .......................................................................................................... 26
Switchgear Room: ............................................................................................................................. 26
Breaker Room: .................................................................................................................................. 27
Battery Room: ....................................................................................................................................... 28
Electrical Control system ..................................................................................................................... 29
Power factor correction and compensation ........................................................................................ 29
Mechanical Section ................................................................................................29
Boilers and Heat Exchangers ............................................................................................................... 29

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 Boilers: ............................................................................................................................................... 29
Heat Exchangers: .............................................................................................................................. 30
Governor ................................................................................................................................................ 30
Different types of machinery ................................................................................................................ 31
Hydraulic press: ................................................................................................................................ 31
Power cutter: ..................................................................................................................................... 32
Bench grinder: ................................................................................................................................... 32
Milling machine: ............................................................................................................................... 33
Engine type Lathe: ............................................................................................................................ 33
Drill machine: .................................................................................................................................... 34
Bench Grinder:.................................................................................................................................. 34
Radial drilling machine: ................................................................................................................... 35
Cooling Systems .................................................................................................................................... 35
Lubrication Oil System..........................................................................................36
Lubrication Oil Types and Functions ................................................................................................. 36
Engine Oil: ......................................................................................................................................... 36
Hydraulic Oil:.................................................................................................................................... 36
Transformer Oil (or Insulating Oil): ............................................................................................... 36
Gear Oil: ............................................................................................................................................ 36
Turbine Oil: ....................................................................................................................................... 36
Grease: ............................................................................................................................................... 36
Oil Storage and Handling ..................................................................................................................... 36
Oil Filtration and Purification ............................................................................................................. 37
Air compressor room:........................................................................................................................... 38
Ventilation room: .................................................................................................................................. 39
Lubrication Oil Pump Starter Panel:.................................................................................................. 39
Lubrication Oil Pump........................................................................................................................... 40
Protection and Instrumentation Section ..............................................................40
Protective Relays and Devices.............................................................................................................. 40
Protection mechanism for Machines ................................................................................................... 41
Starting Machine ............................................................................................................................... 41
Stopping Machine: ............................................................................................................................ 42
Generator protection measures ........................................................................................................... 42

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 Transformer Protection measures ....................................................................................................... 43
PTW and S.P tag ................................................................................................................................... 43
Alarm and Shutdown Systems:............................................................................................................ 44
AVR (Automatic Voltage Regulator) Systems: .................................................................................. 44

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 Introduction to Hydro-Electricity
Hydro-electricity is a way to make electricity
using water. It's like when you have a water
wheel in a river, and the water pushes the wheel,
making it turn. When the wheel turns, it can
generate electricity that we can use to power our
homes, schools, and other things
Here's how it works: Imagine a big dam built
across a river. Behind the dam, there's a huge
amount of water stored. When we open gates in
the dam, the water rushes out with a lot of force.
Figure 1 :Dam
This rushing water turns a special machine called
a turbine. The turbine is connected to a generator,
which is like a magic box that turns the moving Figure 2 Dam

water into electricity.

So, in simple words, hydro-electricity is about
using the power of flowing water to create
electricity. It's a clean and renewable source of
energy that helps us light up our world without
polluting the environment.

Working of Hydro-Electricity:
Let’s explain the working of hydro-electricity:
Basic Principles of Hydro-Electric Generation:
Hydro-electricity is made by the force of moving
water. Imagine a river. When we build a big
wall called a dam across the river, it creates
a kind of lake behind it. This lake stores lots
of water.

Figure 2: Working of Hydropower plant

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Role of Dams and Reservoirs:
The dam holds back the water, creating a big reservoir or lake. When we want to make
electricity, we open gates in the dam to let the water flow out. As the water rushes out, it has a lot
of energy, like when you let water out of a balloon, it goes fast.
Water Flow and Turbines:
This fast-flowing water spins a special machine called a turbine. Think of a turbine like a big fan
or wheel. When the rushing water hits the turbine, it makes it spin around really fast. And guess
what? When the turbine spins, it's connected to something called a generator, which is like a
magic box. This magic box turns the spinning motion of the turbine into electricity, just like how
a bicycle dynamo can light up a bulb when you pedal.
So, in a nutshell, hydro-electricity is made by using the energy of flowing water. The dam and
the turbines work together to change the water's energy into electricity that we can use to power
our homes and devices.

Generation of Hydro-Electricity:
According to Global Data, hydropower
accounted for 24% of Pakistan's total installed
power generation capacity and 24% of total
power generation in 2021.Generating hydro-
electricity is like using the power of water to
make electricity. Here's how it works:

Figure 3: Generation of hydro-electricity

Dam:
Imagine a big wall built across a river. This wall is called a dam. The dam blocks the river and
creates a large lake behind it.
Water Flow:
Now, when we want to make electricity, we open gates in the dam. This allows the water from
the lake to flow out. When it flows out, it goes downhill, and this creates a lot of energy.

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Turbines:
Down below, we have a special machine called a turbine. Think of it like a big spinning wheel.
When the rushing water from the dam hits this wheel, it makes it spin really fast.
Generating Electricity:
The spinning turbine is connected to something called a generator. This generator is like a
magical box. It takes the spinning energy from the turbine and turns it into electricity.

So, in simple terms, hydro-electricity is made by letting water flow downhill from a dam. As it
flows, it spins a turbine, and that spinning motion is turned into electricity. It's like nature's way
of helping us light up our homes and schools.

Hydro-Electricity generation in the World vs. Pakistan

Pakistan:
As of June 30, 2022, Pakistan had the ability to generate electricity with a total capacity of
43,775 megawatts. This electricity was produced using various sources:
Hydroelectric: Around 10,635 megawatts were generated by using the power of flowing water
in rivers and dams to create electricity.

Figure 4: Analysis of Pakistan hydropower plants

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World:
In 2022, the production of hydroelectricity grew by nearly 70 terawatt-hours, which is about a
2% increase, totaling 4,300 terawatt-hours. Hydroelectric power continues to be the leading
source of renewable electricity, generating more than all other renewable technologies combined.
Top 5 countries generation graph:

Figure 5: World hydropower plant Generation

Chashma Hydropower Station

The Chashma Hydropower Project in Pakistan is situated near Kundian in the Mianwali District
of Punjab. It's a hydroelectric power plant with a planned capacity of 184 megawatts of
electricity. This facility has eight separate units, with the first one becoming operational in 2001.
The operation of this project is managed by the Water and Power Development Authority
(WAPDA).
The power station has a total capacity of 184 megawatts, and it consists of eight bulb-type
turbine units, each with a capacity of 23 megawatts. These bulb turbines, which are a new
technology in Pakistan, were first put into operation in January 2001, and by July 2001, all eight
units were up and running. Transmission lines are of 132kV & generators are of 11 kV. Kaplan

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type bulb turbine is used. Distributes electricity to Chashma bank canal I and II, DI khan and
Wan bhachran.

Figure 6: Single unit Layout Model

Important Facts about Chashma Hydropower Station

Exploring Turbine
Turbine Manufacturer: Turbine type:
Fuji, Japan Bulb type (Kaplan)

Height of Head
Maximum: Minimum: Hydraulic Head:
11.58m 3.96m 8.35m

Transformer
Transformer manufacturer:
GEC, Alstom France

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Longitude and Latitude
Longitude: Latitude:
71.37062 32.43482

Generator guide bearing: (Oil flow)

Normal(liter/min): Maximum(liter/min): Minimum(liter/min):
23 32 16

Turbine guide bearing: (Oil flow)

Normal(liter/min): Maximum(liter/min): Minimum(liter/min):
21 29 15

Thrust guide bearing: (Oil flow)

Normal(liter/min): Maximum(liter/min): Minimum(liter/min):
174 214 122

Salient Features
Length between abutments: Total Bays:
3556 ft. 52 Nos.
Standard Bays: Undersluce Bays:
41 Nos. 11 Nos.
Normal Pond Level: Maximum Storage Level:
642 ft. 649 ft.
Maximum Flood Discharge: Maximum Intensity of Discharge:
950000 Cs. 300Cs. Per ft.
Width of Carriage: Length of Navigation Lock:
Way 24 ft. 155 ft.
Width of Navigation Lock: Area of Reservoir :
30 ft. 139 Sqm.

Generator guide bearing temperature

Alarm: Tripping:
65° C 75° C
Stator winding temperature
Alarm: Tripping:
82-85° C 125° C

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Transformer winding:
Alarm: Tripping:
102° C 112° C

Transformer oil:
Alarm: Tripping:
95° C 105° C

Effect on Environment
1. Water Flow and Ecosystem:
The construction of the Chashma Hydropower Plant can significantly alter the natural flow of
water in the river. This alteration can have both positive and negative impacts on the surrounding
ecosystem. Changes in water flow patterns may affect the migration patterns of fish and other
aquatic organisms, potentially disrupting their natural habitats.
2. Reservoir Creation:
The plant may involve the creation of a reservoir, which can lead to the flooding of large areas of
land. This flooding can result in the loss of vegetation, wildlife habitats, and even human
settlements. It can also lead to the displacement of local communities, requiring the resettlement
of affected populations.
3.Sedimentation and Water Quality:
Building the Chashma Hydropower Plant could result in sediment buildup in the reservoir,
potentially altering the shape of the riverbed downstream and affecting aquatic environments.
Furthermore, operating the plant may change water quality due to shifts in water flow and the
release of water with varying temperature and oxygen levels. In simpler terms, constructing this
power plant might cause mud and dirt to collect in the reservoir, which could change the way the
riverbed looks downstream and harm the creatures that live there. Also, when the plant is
running, it might make the water's quality worse because it could make the water warmer and
have less oxygen in it.

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 Operational Section
Turbine types and Classification
Turbine types

Turbine Types

Reaction Impulse Turbine

Turbine

Kaplan
Pelton turbine
(vertical,horizontal)

Francis
( Vertical,horizontal)

Propeller Bulb type (Moveable blades)

(Fixed blades)
-3 to 34

Kaplan turbine:

Figure 7: Kaplan Turbine

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Turbine Basics:
A Kaplan turbine is a type of water turbine used to generate electricity from the kinetic energy of
flowing water.
It consists of several important components, including the runner (the spinning part), blades, and
a shaft.
Runner and Blades:
The runner is the heart of the Kaplan turbine. It's a cylindrical shape with blades attached to it.
The blades are curved, like airplane wings. This curvature is crucial because it allows the turbine
to efficiently capture energy from the water as it flows through.
Water Flow:
In the Chashma Hydropower Plant, water from the river is directed into the turbine.
As the water enters the turbine, it flows over the curved blades of the runner.
The kinetic energy of the flowing water causes the runner to spin. This spinning motion is what
generates mechanical energy.
Mechanical to Electrical Energy:
As the runner spins, it's connected to a shaft, which, in turn, is linked to a generator.
The spinning motion of the runner is converted into mechanical energy, which is used to turn the
generator.
The generator then transforms this mechanical energy into electrical energy, which is the
electricity we use in our homes and industries.
Adjustable Blades:
One unique feature of Kaplan turbines is that their blades can be adjusted.
By changing the angle of the blades, the turbine can adapt to different water flow conditions.
This is important because rivers don't always have a consistent water flow; it can vary depending
on the season and other factors.
Adjusting the blades allows the turbine to operate efficiently even when the water flow is low or
high.

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Efficient Design:
Kaplan turbines are known for their high efficiency and versatility. Their ability to adapt to
changing water flow conditions makes them ideal for hydropower plants located in rivers with
variable water levels.
Chashma Hydropower Plant:
Shortly , the Kaplan turbine at the Chashma Hydropower Plant is like a big, spinning wheel with
curved blades that turns the energy of river water into electricity. It's designed to work efficiently
in different river conditions and is a key part of how the power plant generates electricity for
people to use.

Figure 8: Turbine specifications

Turbine Control panel

In a hydropower plant like Chashma WAPDA, a turbine panel refers to a control system or a set
of control panels that are used to manage and operate the turbines within the plant. Here's an
explanation of what a turbine panel is and its role in such a power plant:

Figure 9: Turbine Control Panel

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Wicket gates and draft tube gates of turbine:
A draft tube gate and wicket gates are components commonly found in hydropower plants,
particularly in the turbine section.
A draft tube gate is a large, movable gate located at the end of the draft tube. The draft tube is a
structure that helps control the flow of water exiting the turbine of a hydropower plant. The draft
tube gate can be opened or closed to regulate the flow of water and adjust the output of the
turbine. By controlling the flow through the draft tube, the gate helps optimize the efficiency and
performance of the turbine. Draft tube gate opening takes almost 8min for proper opening and
closing takes 1.5min.
On the other hand, wicket gates are smaller, adjustable gates located at the entrance of the
turbine. They are typically arranged in a circular pattern around the turbine runner. Wicket gates
control the inflow of water into the turbine. By adjusting the position of the wicket gates, the
operator can control the amount of water entering the turbine, thereby regulating the power
output.
Control System:
A turbine panel is essentially a control system that is responsible for monitoring and controlling
the operation of the turbines in the hydropower plant.
Monitoring Turbine Performance:
The turbine panel allows operators to monitor various parameters related to the turbines. This
includes information such as turbine speed, water flow rate, and the electrical output being
generated.
By keeping an eye on these parameters, operators can ensure that the turbines are running at their
optimal efficiency.
Safety and Protection:
Turbine panels also play a critical role in ensuring the safety of the turbines and the power plant
as a whole.
They are equipped with safety systems and alarms that can detect any anomalies or issues in the
turbine operation. For example, if there's a sudden drop in water flow or if the turbine is running
too fast, the control system can trigger alarms and take corrective actions to prevent damage.
Turbine Control:
Operators can use the turbine panel to adjust and control the operation of the turbines. This
includes starting, stopping, and regulating the speed of the turbines.
They can also control the opening and closing of the turbine's wicket gates or blades to manage
the flow of water through the turbine.

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Efficiency Optimization:
One of the key functions of the turbine panel is to optimize the overall efficiency of the power
generation process.
Operators can make real-time adjustments to ensure that the turbines are working in sync with
the varying water flow conditions in the river, which helps maximize electricity production while
minimizing waste.
Data Logging and Analysis:
The control system typically includes data logging capabilities, which means it records historical
data related to turbine performance.
This data can be analyzed to improve the long-term efficiency and maintenance of the turbines.
Integration with Plant Operations:
The turbine panel is integrated with other control systems within the hydropower plant, such as
those managing the dam, water intake, and electrical generation.
This integration ensures that the entire plant operates smoothly and efficiently.

Excitation Mechanism in Power Plants

The excitation mechanism in a hydropower plant like Chashma WAPDA in Mianwali is a vital
component of the power generation process, specifically in the context of the synchronous
generators (alternators) used to produce electricity. Let's explore what the excitation mechanism
is and its role in such a power plant:
What is Excitation Mechanism?
The excitation mechanism is a system that provides the necessary electrical field (excitation) to
the rotor of the synchronous generator. This electrical field is crucial for generating electricity in
the generator.
Role of Excitation Mechanism:
In a hydropower plant, water flow is used to turn the turbines, which are connected to the
synchronous generators.
The generators consist of a rotor (the spinning part) and a stator (the stationary part).
To produce electricity, there must be a relative motion between the rotor and the stator. This
motion induces voltage in the stator windings, which is then converted into electrical power.
Field Windings:
The rotor of the synchronous generator contains field windings, which are essentially coils of
wire.

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The excitation mechanism supplies electrical current to these field windings, creating a magnetic
field in the rotor.
Synchronization:
The key feature of synchronous generators is that they operate in sync with the grid's frequency.
In many power systems, this frequency is typically 50 Hz or 60 Hz.
The excitation mechanism ensures that the rotor spins at the same speed as the grid frequency,
allowing the generator to produce electricity that is in phase with the rest of the power system.

Figure 10: Generator Specifications

Voltage Regulation:
Another important role of the excitation mechanism is voltage regulation.
By controlling the amount of excitation current supplied to the field windings, the voltage output
of the generator can be adjusted to maintain a stable and consistent voltage level on the power
grid.
Control and Automation:
Excitation systems are often highly automated and controlled by specialized devices and
software.
They continuously monitor the generator's performance and grid conditions, making real-time
adjustments to the excitation level to ensure stable and reliable electricity production.
Protection and Safety:
The excitation system also includes protective features to safeguard the generator from various
faults and abnormal operating conditions, such as overcurrent or overvoltage situations.
In Chashma, WAPDA hydropower plant, the excitation mechanism is a critical part of the
synchronous generators used to convert the mechanical energy from water turbines into electrical
power. It ensures that the generators operate at the correct frequency, maintain voltage stability,
and contribute to the reliable and efficient generation of electricity.

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Voltage and Frequency Control in Turbines
Voltage and frequency control in turbines at Chashma WAPDA, a hydropower plant in
Mianwali, refers to the management and regulation of the electrical output to maintain stable and
consistent voltage levels and frequency on the power grid. Here's an explanation of how this
control works:
Voltage Control:
Voltage is a measure of electrical potential, and it needs to be maintained at a specific level to
ensure the safe and efficient operation of electrical equipment and appliances.
Turbines in hydropower plants like Chashma WAPDA generate electricity, but the voltage
produced can vary depending on factors like load demand and system conditions.
Frequency Control:
Frequency refers to the number of oscillations (cycles) per second in an alternating current (AC)
electrical system. In many regions, the standard frequency is either 50 Hz or 60 Hz. The
frequency must be closely regulated because it affects the timing of electrical devices and the
operation of motors, appliances, and other equipment.Turbines, driven by water flow, are one
source of electrical power generation. The speed at which they turn determines the frequency of
the electricity they produce.

Operational Specifications:
Some operational specifications are as follows:
Machine Volts: Maximum amperes: Excitation current: Excitation voltage:
11KV 1365A 688A 275V
Synchronous Exciter Generator: Frequency: Generator Power
Generator: Stator poles=20 Poles 50 Hz Factor:
Salient pole rotor=70 0.85
Poles
Insulation Class: rpm: Generator Stator Exciter:
F 85.7 Winding: Separately excited
Star Connected
Shaft: External Diameter Internal Diameter of Thickness of Shaft:
Hollow type (servo of Shaft: Shaft: 300mm
mechanism) 900mm 600mm

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 Electrical Section
Transformer
Step-up transformer:

Figure 11: Step-up Transformer

A step-up transformer at Chashma WAPDA, like in many other power plants, plays an important
role in the electrical power generation and transmission process. Here's an explanation of what a
step-up transformer is and its purpose:
What is a Step-Up Transformer?
A step-up transformer is a type of electrical transformer designed to increase the voltage of
electrical energy. It has more turns in its secondary winding (output side) than in its primary
winding (input side).
Purpose of a Step-Up Transformer at Chashma WAPDA:
In a hydropower plant like Chashma WAPDA, the electricity is generated in generators
connected to the turbines. However, the voltage produced by these generators is typically not
suitable for long-distance transmission.
Voltage Increase:
The primary function of a step-up transformer is to increase the voltage of the generated
electricity to a much higher level.
This increased voltage is necessary for efficient transmission of electrical power over long
distances through power lines. Higher voltage reduces energy losses during transmission.
Transmission to Substations:
Once the voltage is stepped up by the transformer, the high-voltage electricity is transmitted
from the power plant to substations located closer to the areas where electricity is needed.
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Distribution to Consumers:
At these substations, other transformers known as step-down transformers are used to reduce the
voltage to levels suitable for distribution to homes, businesses, and industries.
These lower voltage levels are safer for household appliances and devices.
Maintaining Grid Stability:
Step-up transformers also play a role in maintaining grid stability by providing a consistent and
stable supply of electricity to the power grid.

Main components of step-up transformer:

 Core: Provides a path for magnetic flux.
 Primary Winding (Coil): Receives input energy at a lower voltage.
 Secondary Winding (Coil): Outputs higher voltage energy.
 Insulation: Prevents electrical shorts and maintains separation.
 Tap Changer (if applicable): Adjusts voltage ratio.
 Cooling System: Dissipates heat generated during operation.
 Tank: Encloses the transformer and holds insulating oil.
 Bushing: Connects the transformer to external circuits.
 Oil Conservator (if applicable): Manages oil expansion and contraction.
 Breather: Prevents moisture and dust entry while allowing air exchange.
 Pressure Relief Device: Releases excess pressure during faults.
 Buchholz Relay: Detects internal faults and triggers alarms or shutdowns.
 RTD's (Resistance Temperature Detectors): Measure transformer temperature for
monitoring and protection.

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Axillary Transformer:

Figure 12: Axillary Transformer

An auxiliary transformer in a hydropower plant performs various important functions to support

the overall operation of the plant. Here's how it works:
Voltage Transformation:
One of the primary functions of an auxiliary transformer is to change the voltage levels of
electrical energy. It takes in electrical power at one voltage and provides it at another voltage
suitable for various plant equipment and systems.
Supplying Power:
The auxiliary transformer supplies electrical power to the plant's auxiliary and control systems,
which are essential for monitoring, controlling, and protecting the main power generation and
distribution equipment.
Isolation:
It electrically isolates the auxiliary systems from the main generator and transmission system,
ensuring that disturbances or issues in the auxiliary systems do not affect the critical operation of
the main power generation process.
Voltage Regulation: The transformer helps regulate voltage levels within the auxiliary systems,
ensuring that sensitive electronic equipment and instrumentation receive stable and reliable
power.

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Protection:
It may include protective devices such as circuit breakers and relays to safeguard the auxiliary
systems from electrical faults or overloads.
Cooling:
Like other transformers, auxiliary transformers generate heat during operation. Cooling systems,
such as fans or oil cooling, help dissipate this heat, preventing overheating and ensuring efficient
operation.
Monitoring:
Some auxiliary transformers are equipped with monitoring and control systems that allow
operators to observe the transformer's performance and respond to any anomalies or issues
promptly.

Transformer Inspection:
 Examine for oil leaks and bushing sparking.
 Assess oil leakage within RYB windings.
 Inspect for oil and water seepage on the surface cooler.
 Confirm the tightness of nuts and bolts.
 Monitor the oil level in the conservator tank.
 Check the color of silica gel (should be blue, not brown).
 Ensure temperatures are below 80°C for windings and 90°C for oil.
 Verify adequate room lighting.
 Clean insulators and the transformer's exterior.
 Validate the functioning of exhaust fans.
 Conduct meggering of transformer windings.
 Perform oil tests for dehydration and breakdown voltage.

Generator and Alternator

Main Generator:
The synchronous self-excited main generator is the primary generator
responsible for producing electrical power. It is a synchronous generator
that operates in sync with the grid's frequency (e.g., 50 Hz or 60 Hz).
In WAPDA , rotor have 70 poles.

Figure 13: Main Generator

rotor

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Working:
 The main generator is connected to the turbines driven by the water flow in the
hydropower plant.
 As the turbines turn, they spin the rotor of the main generator.
 The rotor is equipped with field windings and produces a magnetic field when energized.
 As the rotor spins, it induces a flow of electricity in the stator windings, which is then
transformed into usable electrical power.

Exciter Generator:
The exciter generator is a smaller generator that provides the necessary direct current (DC)
power to create the magnetic field in the rotor of the main generator. In WAPDA

Working:
 The exciter generator is connected to the same shaft as the main generator's rotor.
 As the shaft turns due to the water turbine's rotation, the exciter generator also spins.
 The exciter generator produces DC power, which is then sent to the field windings of the
main generator's rotor.
 This DC power creates a magnetic field in the rotor, allowing it to generate electricity in
the stator windings, as described earlier.

Coordination:
The exciter generator plays a critical role in controlling the voltage and excitation of the main
generator.
By adjusting the current supplied to the field windings in the main generator's rotor, the exciter
generator can regulate the strength of the magnetic field.
This, in turn, controls the voltage output of the main generator. When more excitation is
provided, the voltage increases, and vice versa.

Voltage and Frequency Control:

Together, the main generator and the exciter generator help maintain the stability of the power
generated in terms of voltage and frequency.
If there is a change in load or system conditions, the exciter generator adjusts the excitation level
to keep the voltage and frequency within acceptable limits.

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Generator control panel:
In the generator control panel, the excitation system supplies the necessary DC power to the field
windings, creating a magnetic field within the rotor. This, in turn, allows the main generator to
produce electrical power. The synchronous check relay continuously monitors the generator's
parameters to ensure synchronization with the grid, while the excitation control system fine-
tunes the excitation to regulate the generator's output voltage and maintain stable operation.

Figure 14: Generator Control Panel

Switchgear and Circuit breaker

Switchgear Room:

Figure 15: GIS room

Gas-Insulated Switchgear (GIS) Room in the Chashma Hydropower Plant is a critical area where
vital components ensure safe and efficient power distribution. It includes SF6 gas-filled cable

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compartments, a 132KV circuit breaker, bus bars, couplers for dual bus bars, main circuit
breakers for all 8 units, earth switches, disconnectors, and current and potential transformers. It
follows a precise procedure, where isolators must be closed before starting the machinery.
During operation, the earth switch must remain open to prevent grounding issues. The GIS
technology used is advanced but costly. This room is crucial for high-voltage control, ensuring
reliable power distribution by isolating faulty units while maintaining power to unaffected ones.
It reduces space and enhances performance through SF6 gas insulation, contributing to stable
power generation.

Breaker Room:

Figure 16: Breaker room

The breaker room at the Chashma Hydropower Plant contains various circuit breakers with
specific specifications. These breakers are responsible for interrupting electrical circuits in case
of abnormalities, like faults or overloads, to protect the equipment and maintain the power
system's integrity.
Each breaker is designed to close all 3 phases, with a system breaking capacity of 25KA and a
making capacity of 62.5KAP. The short-time current is rated at 25KA, and the operating
sequences follow a specific pattern. The frequency is set at 50Hz, voltage at 38KVP, and there's
a 2.7bar rating for current impulse.
There are five different breakers in the room, each serving a specific purpose, such as incoming
and outgoing connections to transformers and switchgear. These breakers are crucial for
preventing electrical faults that could disrupt power supply or cause damage.

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The breaker room is equipped with advanced monitoring and control systems, enabling real-time
supervision and quick responses to any issues. Engineers and operators can efficiently manage
and maintain the circuit breakers to ensure the reliability and safety of the power system.

Battery Room:

Figure 17: Battery room

A single battery is made up of 105 cells connected in a row. Each cell has a power of 2.2V.
When connected this way, the battery gives out 220V of direct current (DC). In the setup, a
charger powered by 400VAC, 3-phase input supplies an AC-DC rectifier. This sends power to
the 105-cell batteries. Then, the power is sent out to units and transmission lines. At the same
time, an inverter changes 230V DC to 230V AC, working like a backup power source. Finally,
the rectifier turns the AC back into 48V DC, which is used for alarms and signals. Different parts
of the setup have names like C+ for control supply, B+ for protection supply, SA+ for signals
and alarms, and TP (positive) and TN (negative) for the inverter supply (for backup).
This battery room is important for starting the powerhouse before any work can be done there.
It's a special place for storing and managing batteries, which are really important for keeping a
steady and dependable power supply. The room is set up to save extra energy when not much is
needed and use it when there's a higher demand for electricity. It's also crucial for using
renewable energy sources by storing extra energy made, making sure there's power all the time.
Battery rooms also help keep the powerhouse stable by quickly reacting to changes in frequency
and voltage. They provide a steady power supply for important systems and make sure batteries
are well taken care of through checks and maintenance. Getting rid of batteries in the right way
and recycling them is also part of being responsible for the environment in power generation.

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Electrical Control system
Here's a concise explanation of each aspect of the electrical control system at WAPDA's
Chashma Hydropower Plant:
 Monitoring and Supervision: Continuous monitoring of electrical parameters.
 Generator Control: Regulates generator voltage and frequency.
 Protection and Safety: Detects faults and ensures safety.
 Synchronization: Aligns generators with the grid's frequency.
 Load Shedding and Balancing: Balances supply and demand.
 Fault Detection and Diagnosis: Identifies electrical faults for troubleshooting.
 Remote Control: Enables remote operation.
 SCADA (Supervisory Control and Data Acquisition): Provides real-time data and
control interfaces.
 Communication: Facilitates inter-component communication.
 Emergency Response: Includes shutdown procedures for safety.

Power factor correction and compensation

Power Factor Correction:
Enhancing power factor by reducing phase differences using capacitors or reactive devices.
Compensation for Reactive Power:
Managing and controlling reactive power to optimize energy use and system efficiency.
Benefits:
Improved power factor and reactive power management lead to reduced losses, increased
capacity, and enhanced voltage stability in the electrical system.

Mechanical Section
Boilers and Heat Exchangers
Boilers and heat exchangers play essential roles in the energy production process at WAPDA
Chashma Hydropower Plant. Here's a brief explanation of their functions:

Boilers:
Boilers are crucial for converting water into steam by using the heat generated from burning
fuels like coal or natural gas. The steam produced is then used to drive turbines, which generate
electricity. Boilers are the heart of thermal power plants and are vital for efficient energy
conversion.

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Heat Exchangers:
Heat exchangers are devices that transfer heat from one fluid to another without them coming
into direct contact. In power plants, they play a critical role in cooling various systems and
components. For instance, they help condense steam back into water after it passes through the
turbines, enabling the cycle to repeat. Heat exchangers also aid in maintaining optimal
temperatures in different parts of the power generation process, ensuring efficient operation and
equipment longevity.

Governor

Figure 18:Governor Control

Governor Mechanism and Its Parts:

Think of the governor mechanism as the conductor of an orchestra, guiding the speed of the
turbine at Chashma Hydropower Plant. It's made up of different pieces, like a motor, pendulum,
pump, pipes, and speed detectors. All of these work together under the control of the oil pressure
governor to keep the turbine running smoothly.
How the Governor Keeps Things Steady:
The governor's job is to ensure the turbine spins at the right speed, even when power demand
changes. It does this by sensing shifts in water flow and speed and adjusting the water flow
through the turbine accordingly. This helps maintain a consistent speed and power output, which
is vital for a stable electrical system.

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Why the Governor Is So Important:
Think of the governor as a middleman between the turbine and the generator. It makes sure the
generator keeps a steady speed, especially when trying to achieve a specific frequency.
Parts That Make It Work:
Inside the governor system, there are several important parts. These include a motor that controls
water flow, a tank for oil distribution, and a network of pipes. Speed detectors act like guards on
the turbine's shaft, telling the governor if the speed changes. Each part plays a vital role in
keeping the turbine running smoothly.
Oil System and Pressure Control:
The governor's effectiveness depends on its oil pressure control system. This system manages the
oil pressure, which, in turn, affects the turbine's speed. Oil pumps deliver the right amount of oil
to different parts of the system, and air compressors fine-tune the pressure, ensuring the turbine
runs smoothly.

Figure 19: Governor Oil pumps

Different types of machinery

Hydraulic press:
A hydraulic press employs hydraulic power from a cylinder and specialized fluid to apply
pressure on materials, facilitating processes such as shaping, bending, and pressing. It comprises
components like a hydraulic cylinder, pump, valves, and control mechanisms. As hydraulic fluid
is introduced into the cylinder, it prompts the movement of a piston, thereby generating force
that is conveyed to a tool or die responsible for forming the work piece.

Figure 20: Hydraulic Press

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Power cutter:
A power cutter is employed to efficiently slice through metal and concrete for the purpose of
repairing or substituting components. Moreover, it assists in sculpting concrete formations like
dam walls, expediting their erection, upkeep, and eventual dismantling. These devices also
facilitate the adjustment of pipes and conduits, guaranteeing the continuous movement of liquids
and other substances within the facility. Finally, power cutters serve a crucial function in urgent
situations by enabling swift cutting to reduce potential hazards and preserve the plant's
operational stability.

Figure 21: Power Cutter

Bench grinder:
A bench grinder is a stationary tool with two spinning wheels that sharpens, shapes, and grinds
materials, especially metal. It's commonly found in workshops and metalworking for jobs like
sharpening tools and smoothing rough edges. The grinder is firmly attached to a workbench and
usually comes with safety elements like adjustable supports and protective shields.

Figure 22: Bench Grinder

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Milling machine:
A milling machine is a tool that uses spinning blades to carve and shape materials, especially
metal. It's vital in metalwork for crafting intricate parts. The material is guided into the blades,
which can be set up and down, side to side, or at different angles. CNC types can be programmed
for exact automation, while manual ones need skilled operators.

Figure 23: Milling Machine

Engine type Lathe:

An engine type lathe is a flexible metalworking tool. It's used for tasks like turning, facing, and
threading. The lathe has a horizontal spindle and a tool that moves to shape the material as it
spins. People operate it by hand, giving them precise control over the cutting.

Figure 24: Engine type Lathe

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Drill machine:
A drill machine, also called a power drill or handheld drill, is a simple but handy tool for making
holes in different stuff. It has a motor that spins the drill bit quickly when pressed against the
material. You can change the drilling speed and use different types of bits for wood, metal, or
plastic.

Figure 25: Drill Machine

Bench Grinder:
A bench grinder is a stationary tool with two spinning wheels that sharpens, shapes, and grinds
materials, especially metal. It's commonly found in workshops and metalworking for jobs like
sharpening tools and smoothing rough edges. The grinder is firmly attached to a workbench and
usually comes with safety elements like adjustable supports and protective shields.

Figure 26: Bench Grinder

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Radial drilling machine:
A radial drilling machine has a movable arm that can rotate and be placed in different positions.
This lets the drilling head reach various spots on the material without moving the material itself.
This setup is handy for drilling holes in big and weighty work pieces. The machine has a motor-
driven spindle for holding and spinning the drill, along with systems to manage the arm's motion
and drilling speed.

Figure 27: Radial Drilling Machine

Cooling Systems
The cooling system in the WAPDA Chashma hydropower plant plays a crucial role in
maintaining optimal operating temperatures. It typically employs a closed-loop system that
utilizes water from the reservoir or a nearby water source.
Water is pumped through a series of tubes or pipes, absorbing heat from various components,
such as generators and transformers. This heated water is then directed to a cooling tower, where
it releases the absorbed heat into the atmosphere through evaporation and convection. The cooled
water is then recirculated back to the plant to repeat the process.
This continuous cycle ensures that the equipment operates within safe temperature ranges,
allowing for efficient and reliable power generation. It's worth noting that specific details of the
cooling system may vary depending on the plant's design and local environmental conditions.

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 Lubrication Oil System

Lubrication Oil Types and Functions

In a hydropower plant like WAPDA's Chashma facility, various types of lubrication oils are used
to ensure smooth operation and longevity of machinery. Here are some common types and their
functions:

Engine Oil:
Engine oil is used in various components such as turbines, generators, and other rotating
machinery. It serves to lubricate moving parts, reducing friction and wear. Additionally, it helps
in dissipating heat generated during operation.

Hydraulic Oil:
Hydraulic oil is crucial for the operation of hydraulic systems within the plant. It provides the
necessary pressure transmission and lubrication for components like valves, actuators, and
hydraulic cylinders.

Transformer Oil (or Insulating Oil):

Transformer oil is used in transformers to provide electrical insulation and to dissipate heat
generated during operation. It also prevents the formation of corrosive by-products within the
transformer.

Gear Oil:
Gear oil is employed in gearboxes and transmissions to reduce friction between gear teeth, thus
preventing wear and ensuring smooth operation.

Turbine Oil:
Turbine oil is specially formulated for use in turbines. It provides lubrication to bearings and
other moving parts, ensuring efficient and reliable operation.

Grease:
Grease is a semi-solid lubricant used in areas where it is not practical to use liquid oil. It adheres
well to surfaces and provides long-lasting lubrication, making it suitable for bearings and certain
mechanical joints.

Oil Storage and Handling

Oil Storage Tanks:
The plant has designated storage tanks for different types of oils used in various equipment such
as turbines, generators, transformers, etc. These tanks are designed to meet safety and
environmental regulations, ensuring containment in case of spills or leaks.

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Oil Quality Control:
Upon receipt, oils are tested to ensure they meet specified quality standards. This involves
checks for parameters like viscosity, moisture content, acidity, and impurity levels.
Regular Sampling and Testing:
Routine samples are taken from the storage tanks and equipment to monitor the condition of the
oils. These tests help identify any degradation or contamination that may require corrective
action.
Handling and Dispensing:
Trained personnel handle the oils to prevent contamination. Clean equipment and proper tools
are used for dispensing and transferring oils to and from storage tanks.
Waste Oil Management:
Disposal of used or degraded oil is carried out in accordance with environmental regulations.
This may involve recycling, reclamation, or proper disposal methods.

Oil Filtration and Purification

Each unit requires about 24,000 to 25,000 liters of oil. Out of this, 17,000 liters are used for
lubrication. There are two storage tanks, both of the STK-20KL model from SANMI
CORPORATION, JAPAN. Each tank can hold up to 20 cubic meters of oil and weighs 3000
kilograms.
The purification process has several steps:
Heating: There are 8 heaters in the system to help separate water from the oil.
Circulation and Filtration: The oil moves at a speed of 1700 rotations per minute. During this,
water in the oil evaporates. The oil goes through 78 discs that work like filters, catching
impurities.
Water Separation: After heating and circulation, water is taken out of the oil. It collects in a
globe-like structure and is sent to a drainage system.
Final Filtration: The oil that's now free from water and impurities goes through a paper filter
for an extra cleaning.
Returning to Clean Tank: The purified oil goes back to a clean storage tank, ready for use.
In the end, the Oil Purification Plant efficiently gets rid of water and impurities from the oil. It
does this by heating, circulating, filtering, and separating. The cleaned oil is then stored in a
special tank, ensuring high-quality oil is available for various uses.

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 Figure 28: Oil Purifier

Air compressor room:

An air compressor room houses machines that boost the pressure of gases, usually air, for tasks
like running turbines and mechanical operations. They're powered by sources like electric
motors. In Combined Heat and Power (CHP), there are two main types of compressors.
The first one, called the Station Air Compressor, uses a piston to pressurize air. It's a medium-
sized machine with two stages and can compress air up to 40 bar. In CHPP setups, it usually
compresses air to around 15 bar. This compressed air is used for jobs like maintaining generator
brakes and other general purposes.
The second type, the Governor Air Compressor, also uses a piston to compress air. It's medium-
sized and can reach air compression levels of 800 psi. The compressed air from this type is used
in governor systems and firing fitting systems.
These compressors in CHP setups are vital, efficiently compressing air to different pressures for
specific tasks.

Figure 29: Air compressor Rom

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Ventilation room:
The place is also called HVAC, which stands for heating, ventilation, and air conditioning
system. There are six units for handling air for ventilation, four for operational units, one for the
left service area, and one for the right service area. This room is like a control center for
managing air flow and quality in the whole place. It has special systems to control temperature,
humidity, and keep the air clean. The main goals are to make sure there's enough fresh air,
prevent dangerous gases from building up, get rid of extra heat from machines, and keep
conditions right for efficient work.
In this room, there are machines like fans, filters, systems for getting rid of used air, and tools to
control temperature. By keeping the air moving and making the place comfortable, this room
helps the power plant stay safe, work well, and be productive.
Also, there are things called DPS (differential pressure switches) here. They watch and manage
the difference in pressure between two spots in the ventilation system. This helps make sure the
air flows right and stops problems that might come from pressure differences. By checking the
pressure where fresh air comes in and where used air goes out, the switch can find issues like
blocked filters or things blocking the airways. If the pressure difference is too much, the switch
does something, like setting off an alarm, stopping the system, or telling maintenance. This keeps
the air moving well, keeps it clean, and stops possible dangers in the ventilation system of the
power plant.

Lubrication Oil Pump Starter Panel:

The lubrication oil pump starter panel in a WAPDA hydropower plant initiates and monitors the
operation of lubrication oil pumps, ensuring proper lubrication of machinery, with automated
controls and safety features for optimal performance and protection.

Figure 30: Lubrication Starter Panel

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Lubrication Oil Pump
Draft Tube Gates:
The lubrication oil pump ensures that the moving parts of the draft tube gates, which control the
water flow exiting the turbine, operate smoothly. It supplies lubricating oil to the necessary
points to reduce friction, allowing the gates to open and close efficiently without causing
excessive wear.
Wicket Gate Opening:
The wicket gates are adjustable vanes located within the turbine. The lubrication oil pump plays
a crucial role in keeping the wicket gates well-lubricated, enabling them to move freely. This
ensures precise control over the flow of water into the turbine, optimizing power generation.

Figure 31: Lubrication pumps

Protection and Instrumentation Section

Protective Relays and Devices
The system incorporates CSZ06 single coil relays, capable of manipulating multiple sets of
contacts upon receiving power. These relays provide options for both Normally Closed (NC) and
Normally Opened (NO) configurations. When the coil receives power, the relay alters the state of
its contacts, closing previously open ones and vice versa. This transition occurs regardless of the
relay's power status. Each unit in the powerhouse connects approximately 5 to 6 CSZ06 relays,
serving diverse roles in alarm systems and control mechanisms.
These relays are pivotal in various scenarios. For example, one connected to a pressure switch
monitors the governor's oil pressure. If it falls below a specific threshold, the relay activates,
prompting a series of actions. One contact may sound an alarm, another might trigger a governor
shutdown, while others manage mechanical and electrical shutdown procedures. The
incorporation of multiple relays prevents the simultaneous closure of numerous contacts, which
could hinder fault identification. While the CSZ06 relay is the most commonly used, other

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models like CSD3 and CSD4 also have applications in alarm systems and control switching.
These relays oversee the operation and shutdown of various auxiliary systems within the
powerhouse, with their coil configurations encompassing both DC and AC-DC variations.

Figure 32: Protective Relays

Protection mechanism for Machines

Starting Machine
Checking Shaft Seals and Flow:
Verify that pump and bearing shaft seals are properly filled and that flow conditions meet
requirements. Before initiating, ensure pre-start indicators don't show red or yellow alerts.
Failure to meet these conditions will prevent the activation of the start pulse.
Preparation for Startup:
Set controls to auto mode, give a pulse to the governor, release brakes, and fully open the Draft
tube gate to 100%. Confirm proper functioning of the lube oil pump for bearing lubrication.
Reducing Shaft Friction:
The high-pressure pump lifts the shaft while at rest to minimize friction. This is especially
effective when the machine is stationary.
Gradual Wicket Gates Opening:
Gradually open the Wicket Gates based on a preset signal, achieving an opening of 10-12%.
Synchronization Process:
At 85.7rpm, engage the field circuit breaker to initiate a flashing sequence (3-4 seconds) before
the conductor opens, completing the 11KV process. The synchro check relay then verifies
system voltage, unit voltage, frequency, phase-phase angle, and voltage regulation. This relay
enables synchronization of up to three units simultaneously.

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Stopping Machine:
Reducing Load and Closing Gates:
Gradually reduce load from the operating level of 23MW to around 5MW, and send a pulse to
start closing the Wicket Gates. Simultaneously, close the draft tube gate.
Governor-Driven Braking:
When the machine's speed reaches 15%, the governor activates an automatic braking mechanism,
ensuring controlled deceleration.
Runner Blades Repositioning:
As brakes engage and the unit shuts down, the runner blades return to their 0 position.
Scheduled Maintenance Shutdown:
After applying brakes and closing the unit, schedule a maintenance shutdown for approximately
15-20 days. This downtime is essential for regular maintenance procedures.

Generator protection measures

Generator protection measures include:
Protection Against Negative Sequence Fault in Generator:
Safeguarding the generator from imbalances in its three phases, which can lead to damage or
malfunction.
Backup Safeguard for Generator Phase Fault:
Providing secondary defense in case of phase-related issues within the generator, ensuring
reliable operation.
Guarding Against Ground Faults in Generator Stator:
Preventing damage due to unintended electrical paths to the ground in the stator winding of the
generator.
Protection from Differential Faults in Generator:
Detecting and responding to discrepancies between input and output currents, safeguarding the
generator.
Fault Detection by Reverse Power Relay:
Monitoring for abnormal power flow from the generator, preventing potential damage or
inefficiencies.

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Safeguarding Against Over Induction:
Preventing damage to the generator caused by excessive magnetic fields induced by high
currents.
Tripping on Excessive Voltage:
Automatically disconnecting the generator when voltage levels exceed safe operating limits.
Alerting on High Voltage Levels:
Providing a warning signal when voltage levels approach potentially unsafe thresholds.
Overseeing Exciter Current in Generator:
Monitoring and regulating current levels in the exciter circuit to prevent overloading.

Transformer Protection measures

Transformer protection measures include:
Differential Protection for Transformer:
Ensuring the transformer's internal current flow is balanced, detecting any abnormalities that
may indicate a fault.
Backup Protection Against Transformer Earth Fault - TAS1210:
Providing secondary defense mechanisms in the event of an earth fault in the transformer, using
the TAS1210 system.
Backup Protection Against Transformer Earth Fault - TR11:
Offering an additional layer of protection in cases of earth faults in the transformer, utilizing the
TR11 system.
Backup Protection Against Transformer Phase Fault - TA311:
Providing supplementary safeguards for the transformer in the event of phase-related issues,
employing the TA311 system.
Restraint Earth Fault Backup Protection for Transformer - 87REF:
Offering extra protection against earth faults in the transformer, utilizing the 87REF system to
restrain potential damage.

PTW and S.P tag

PTW (Permit to Work) is a crucial safety procedure. It ensures that before any potentially
hazardous work is conducted, a formal authorization is obtained, specifying the nature of the

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work, associated risks, and necessary precautions. On the other hand, S.P (Switching Program)
refers to a structured plan for isolating and de-energizing electrical equipment during
maintenance or repair, safeguarding personnel and equipment from electrical hazards. It outlines
the steps to be followed for safe isolation and re-energization of the equipment.

Alarm and Shutdown Systems:

the Alarm and Shutdown Systems are crucial components of the safety and control infrastructure.
These systems are designed to monitor various parameters and conditions within the plant. When
abnormal or potentially dangerous situations arise, the alarm system provides immediate
notifications to operators. If a critical threshold is breached, the shutdown system is triggered,
automatically halting specific processes or equipment to prevent further escalation of the issue.
This dual system ensures a rapid response to any emergencies, helping to safeguard both
personnel and the plant's operations.

AVR (Automatic Voltage Regulator) Systems:

Automatic Voltage Regulator (AVR) system plays a crucial role in safeguarding electrical
equipment. It continuously monitors the voltage levels within the plant. If the voltage deviates
from the specified range, the AVR system swiftly adjusts the excitation levels of the generator to
maintain a steady voltage output. This prevents overvoltage or under voltage conditions that
could potentially damage equipment. Additionally, the AVR system acts as a protective barrier
by ensuring that the electrical grid receives a stable and reliable power supply. This contributes
to the overall stability and reliability of the hydropower plant's operations.

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