Design of a generating substation with the description of designing a transformer. Here we show some basic components of a substation. and we also show the parameters and calculation to design a transformer of a specific ratings.

2. INTRODUCTION
 A substation is a part of an electrical generation, transmission,
and distribution system.
 ​​​​​​​​​Substations are important components of the electrical
infrastructure required to keep reliable electricity available for
customers.
 The main functions are to receive energy transmitted at high
voltage from the generating station , reduce the voltage to a
value appropriate for local distribution and provide facilities
for switching.

3. Classifications of Sub-station
 On basis of Nature of duties
 Step-up or Primary Substation
 Primary Grid Substation
 Step-down Substation
 On basis of importance
 Grid Substation
 Town Substation
 On basis of design
 Indoor type Substation
 Outdoor type Substation
o Pole mounted Substation
o Foundation mounded Substation
 On basis of Service Rendered
 Transformer Substation
 Switching Substation
 Converting Substation
 On basis of Operating Voltage
 High Voltage Substation
 Extra High Voltage Substation
 Ultra- High Voltage Substation

4. STEPS OF DESIGNING A SUBSTATION
 Step-1 : Selection of a substation switching system
 Step-2 : Preparation of a key plan which should show the location of all components
of a substation and their interconnections
 Step-3 : Selection and ordering of equipment
 Step-4 : Engineering support for licensing and permitting
 Step-5 : Civil and structural design
 Step-6 : Electrical layout design
 Step-7 : Control design
 Step-8 : Construction support

5. LAYOUT OF SUBSTATION
Single Bus Bar Mesh Substation One and a half Circuit
Breaker

6. Typical Components of a Power Plant
Substation (Switchyard)

7. SINGLE LINE DIAGRAM 220KV
SWITCHYARD, MTPS,DVC

8. TRANSFORMER
 A transformer is an electrical device that transfers electrical energy
from one coil called primary coil to other coil secondary coil
through electromagnetic induction .
 Transformers are classified into two types based on the conversion
of voltage level. These are step-up and step-down transformer.
 Different transformer used in generating substation
 Generator Transformer
 Station Transformer
 Unit Auxiliary Transformer
 Instrument Transformer

9. DESIGN OF TRANSFORMER
Specification of transformer Assumptions

10. Core design

11. Core design
Window dimensions

12. Core design
Yoke parameters

13. Winding design
 Calculation of current magnitude
 Calculation of cross section area
 Calculation of number of turns

14. Winding design
Calculation of Length of Secondary
Winding
Calculation of Length of Primary
Winding

15. Winding design
Calculation of Winding Loss

16. Electrical parameters
Efficiency

17. Tank design
 Cooling tubes

18. POTENTIAL TRANSFORMER
 Used to step-down high voltage to lower voltage level in order to make
measurement easy and optimized.
 Primary winding having higher number of turns connected to high voltage
side.
 Voltmeter has very high resistance thus, PT behaves as an transformer
operating on no load.
 Since load is low so, VA rating of PT is low in range of 50 to 200 VA.
 One end of secondary is connected to the ground for safety reasons

19. CURRENT TRANSFORMER
 Used to step-down high current to lower current level in order to make measurement
easy.
 Primary winding having lower number of turns connected to high current side.
 Secondary winding having higher number of turns connected to measuring
instrument.
 Secondary should not be open-circuit ,to protect high voltage across terminals.
 The current error is due to the watt loss component of the excitation current .
 The phase angle error is proportional to the reactive component Ir.
 The ratio error can be corrected by an amendment to the turns ratio,

20. RELAY
 Relay is the device that open or closes the contacts to cause the operation of the
other electric control
 Gives the commands to the circuit breaker on fault detection.
 There are two configurations NO(normally open) and NC(normally closed).
 TSM(time setting multiplier) is used to vary response time of relay.
 PSM(plug setting multiplier) is used to set the pick up current level of the
relay.
 Rotating disc is placed on bearings called jewel bearing to decrease friction

21. CIRCUIT BREAKER
 Used to open the circuit carrying current, based on relay
signal.
 Circuit breaker rating is selected based on most severe fault
(LLG).
 In order to quench arc proper arc quenching medium and
designs are used.
 Types:
• SF-6 – Sulphur Hexa Flouride Breakers (36 kV to 765 kV) very
good arc quenching as well as insulating properties which make
it ideally suitable for use in a circuit breaker.
• Vacuum circuit breakers(up to 33 kV)- Consists of small
cylinder enclosing the moving contacts under a high vacuum.
• Air Blast Circuit Breaker 11 to 1100 KV

22. SELECTION CRITERION OF RELAYS &
CIRCUIT BREAKER
Specifications of Relay
 Coil Resistance
 Coil voltage
 Carry current
 Maximum switch Current
 Maximum switch Voltage
 Release Time
 Thermal Emf
 Life Expectancy
Specifications of Circuit Breaker:
 Making Capacity
 Breaking Capacity
 Rated Voltage
 Rated Current
 Rated Frequency
 Operating Duty
 Short circuit Current

23. INSULATORS
 Insulators are used to protect current carrying wires from human contact and natural
corrosion.
 Insulator has to withstand the potential stresses between conductor and earth.
 The shortest distance between conductor and earth, surrounding the insulator body is known as
flashover distance.
 Types:
• Pin Insulator ( up to 33 kV )
• Post Insulator
• Suspension Insulator-
• Strain Insulator
• Stay Insulator
• Shackle Insulator
Pin type Post type Suspension type
Shackle type Strain type Stay type

24. ISOLATORS
 Isolators are used to remove a part of the line for maintenance purpose.
 Isolators work on no load i.e. current flowing through them during operation in zero.
 Isolators are generally used on both side of the circuit breaker.
 Types of isolators-
• Single Break Isolator- Only one terminal connects and disconnects
• Double Break Isolator- Has locking mechanism
• Pantograph Isolator- Works on forces of stress or tension, and usually no locking
mechanism is present .
 Isolator can be used to connect a auxiliary line when main line is under maintenance.

25. LIGHTNING ARRESTER
 Lightning arrester are used for protection from lightning and
switching surge.
 Lightening leads to very high voltage which can cause insulator
breakdown.
 Any transient wave with a voltage peak exceeding the spark over
voltage must cause it to break down.
 The breakdown current is passed to ground by the arrester.
 Lightning arrester are placed close to the equipment that is to be
protect.

26. COMMON BUS CONFIGURATION
 SINGLE BUS
Consist of one main bus which is energized all the time and to which all circuits are connected.
 SECTIONALIZED BUS
This arrangement is basically two or more single bus schemes, each tied together with bus
sectionalizing breakers.
 MAIN AND TRANSFER BUS
consists of two independent buses, one of which, the main bus, is normally energized. Under normal
operating conditions, all incoming and outgoing circuits are fed from the main bus through their
associated circuit breakers and switches.

27. COMMON BUS CONFIGURATION
 RING BUS
A ring bus configuration is an extension of the sectionalized bus arrangement and is accomplished by
interconnecting the two open ends of the buses through another sectionalizing breaker.
 BREAKER-AND-A-HALF
In this arrangement, three circuit breakers are used for two independent circuits; hence, each circuit
shares the common center circuit breaker, so there are one- and-a-half circuit breakers per circuit.
 DOUBLE BREAKER–DOUBLE BUS
In the double breaker–double bus configuration, any circuit breaker can be removed from
service without interruption of any circuits. Faults on either of the main buses cause no circuit
interruptions. Circuit breaker failure results in the loss of only one circuit.

28. LOAD FLOW STUDY- THE NECESSITY
AND IMPORTANCE
 A power system being an electric network model involving complex powers rather than impedances, the direct analysis of the
circuit is not possible. So, we use power flow study to plan and design the future expansion of power systems and optimize the
operation of existing systems.
 Load Flow study provides information such as magnitude and phase angle of voltage at each bus and the real and reactive power
flowing in each line
 Once we know the four quantities (P,Q,V,𝛿) for a particular bus in a power system network, we can proceed to calculate line flows
and losses occurring in between the lines connecting the buses.
 Hence, the data obtained from load flow study can be used for economic scheduling of generators, finding steady state value,
plotting voltage profile of the system and for future expansion of the power system importantly.
 Moreover algorithms can be developed for such computations making calculations much less troublesome, accurate and fast.
Accordingly, Gauss Seidel and Newton Raphson have come out on top as the most preferred formulations.

29. Conclusion
Substation is the heart of the electric power system, so the design should be
such that it provides continuous, quality and desired power at the distribution
end with least voltage drop. Moreover, substation design demands the most
careful attention to detail in power system due to the fact that they are operate
in the open at very high voltages (not usually lesser than kV) and involve
electromagnetic fields of considerable strength which may have detrimental and
hazardous effects on the surroundings if not taken care of properly.

30. GROUP - 3
 SPANDAN PAUL (13001616037)
 SOURADEEP MULLICK (13001616038)
 SIDDHARTHA BASU (13001616042)
 SHAKYA ACHARYA (13001616046)
 SAYANTAN KUMAR CHATTOPADHYAY (13001616047)
 SAYAN SARKAR (13001616049)
 SAURAV BASAK (13001616051)