ee381 - power systems
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EE381 - Power Systems
S. Sivasubramani
Associate ProfessorElectrical Engineering Department
Indian Institute of Technology Patnawww.iitp.ac.in/~siva
Overview
Power Systems
Indian Power Sector - An Overview
Syllabus
Books
Course Mechanics
Power Systems
Power systems have the following three components.
1. Generation - Source of Energy
2. Transmission - Transmission of Energy over long distance(close to the speed of light)
3. Distribution - Consumption of Energy
I Electric Energy is seldom used in its form.
I It is easy to convert from other forms and transmit fromsources to loads.
I Power system is the most complex system on earth.
I In interconnected systems, the frequency has to be the same.In India, it is 50 Hz. In some countries, it is 60 Hz.
Generation
Electric energy is generated at generating stations by convertingother forms of energy.
1. ConventionalI ThermalI Hydro (Renewable)I Nuclear
2. Non Conventional (Renewable)I SolarI WindI BiomassI TidalI Geo-ThermalI Small HydroI Waste
Renewable Energy Sources (RES)
RES have unlimited resources. But they are intermittent.
Structure of a Power System
T1
Transmission LineG
T2 T3
DomesticCustomers
CommercialCustomers
Sub Transmission LineIndustrial Customers
Practical System
Interconnected Systems
Reasons for interconnections
1. To improve reliability
2. To improve economy
I Several power systems are interconnected to form a grid.
I Several regional grids are interconnected to form a nationalgrid.
I Interconnections are done at Transmission networks.
I In interconnected systems, the frequency of generation mustbe the same.
Power System
Source : NPTEL
Grid Frequency
<49.90 <49.97 49.7-49.8 49.8-49.9 49.9-50.0 50.0-50.1 50.1-50.2 49.90-50.05 49.7-50.2 49.97-50.03 50.05-50.1 >50 >50.03 >50.05 >50.2 <49.95 49.95-50.05 49.90-49.95
4.28 15.25 0.16 4.12 22.87 67.71 5.14 63.50 100.00 32.51 27.09 72.84 52.23 32.22 0.00 10.69 57.08 6.41
50.023 0.0375 0.0569 46.8 FDI: 36.5
Max 50.196 0:03:50 Max 50.132 0:15:00 198 0:02:47
Min 49.789 18:51:50 Min 49.854 19:00:00 79 0:03:48
135
133
Source : AGRA 10 Sec. (8640 samples)
<49.7
0.00
8:45:40
Instantaneous Frequency 15 minute Average Frequency No. of excursions Average time freq per excursion remains
above 50.03 Hz below 49.97
below 49.97 Hz above 50.03
above 50.00 Hz
below 50.00 Hz No. of hours freq outside
49.9-50.05 Hz
Average Frequency : Frequency Variation Index : Standard Deviation : Mileage:
POWER SYSTEM OPERATION CORPORATION LIMITED
NATIONAL LOAD DESPATCH CENTRE, NEW DELHI
Frequency profile for 19-Jul-2021 (Monday)
0 10 20 30 40 50 60 70 80 90 100
49.75
49.80
49.85
49.90
49.95
50.00
50.05
50.10
50.15
50.20
50.25
00:0
0
01:0
0
02:0
0
03:0
0
04:0
0
05:0
0
06:0
0
07:0
0
08:0
0
09:0
0
10:0
0
11:0
0
12:0
0
13:0
0
14:0
0
15:0
0
16:0
0
17:0
0
18:0
0
19:0
0
20:0
0
21:0
0
22:0
0
23:0
0
Source : POSOCO
Indian Power Sector - An Overview
I India is the third largest producer of electricity (more than 1TU1 a year) in the world.
I India is also the third largest consumer of electricity in the world.
I T& D losses are 21 %.
I However , the per capita energy consumption is 1,208 kWh perperson per year.
I It is low compared to many countries. For example, US : 12,154& China : 4,617
I It is even lower than the world average (3,081 kWh).
11 TU = 1,000,000,000,000 kWh
Installed Capacity
The installed capacity as on 31-05-2021 is approximately 383 GW.
Type Capacity (MW) % of TotalThermal 2(Coal, Oil & Gas) 234,728 61 %
Hydro 46,209 12 %
Nuclear 6,780 2 %
RES 95,656 25 %
Total 383,374
I The peak demand in May, 2021 was 184.503 GW.
I There was a deficit of 0.2 % .
Source : Central Electricity Authority, Ministry of Power, GoI
2Coal based power plants account for 90 %
Installed Capacity - Sector Wise
Private
48%
State
27%
Central
25%
Electricity Generation in May 2021
Total electricity generation in May 2021 was 118.09 BU.
Thermal
74%
Nuclear
3%
Hydro
11%
Renewable
12%
Most of the energy is still from Thermal.
Thermal Power Plant
What We will study in EE381..
We will analyze power systems under
I steady state conditions
I abnormal conditions
In order to analyze, every component of power systems has to bemodeled.
I Generator
I Transformer
I Transmission line
I Load
Since the steady state model of synchronous machines andtransformers have already been studied in EE280, we will onlymodel the following in this course.
I Transmission line
Loads are usually considered as
1. Constant power
2. Constant impedance
3. Constant current
We usually simplify any analysis at the cost of accuracy....
Syllabus
I Basic Concepts
I Line Parameter Calculation
I Performance of Transmission lines
I Per unit calculation
I Network Matrices
I Load Flow
I Economic Dispatch
I Fault Analysis
I Power System Stability
Books
Course Mechanics
Since the semester is online, the following pattern may be adopted.
I Five Quizzes - 40 %
I Mid Sem (Assignment)- 25 %
I End Sem (Mostly Assignment) - 25 %
I Attendance and Sincerity - 10 %
Course Page
Refer to my web page.
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