1. EE 207: Fundamentals of Electrical Power Systems
Chapter 2
Power Systems: An Overview

2. Introduction
Support Components
Main Components

3. Supply of Electricity

4. Electrical Systems Demand
Electricity energy cannot be stored.
Generate electricity based on demand.
Total power drawn by consumer fluctuates depends on the time of day and seasons.
Demand Curve
Plot each demand of electricity by consumer daily/annually

5. Demand Curve

6. Load Duration Curve 3 types of load Base load Intermediate loads
Has to be fed 100% of the time.
Intermediate loads
Have to be fed <100% of the time.
Peak load
May occur 0.1% of the time.

7. Load Duration Curve Plot the duration of each demand on annual based.
100% : 8760hrs

8. Load Duration Curve Base-power stations Intermediate-power stations
Deliver full power at all times
Nuclear, coal-fired, hydro stations,…
Intermediate-power stations
Respond relatively quickly to changes in demand
Usually by adding/removing generating unit
Hydropower stations
Peak-power stations
Deliver power for brief intervals during the day
Put into service very quickly
Equipped with prime movers that can be started up in a few minutes
Diesel, pumped-storage turbines, gas turbines etc.

9. Reduce the voltage 33kV,11kV
Power System Diagram
Generation
Step-up transformer (↑ voltage,↓current)
Grid System (500kV, 275kV, 132kV, 66kV)
Reduce the voltage 33kV,11kV
Transmission
Distribution
Loads
3 phase V, single phase V

10. Power System
AROUND TOWN & RESIDENTIAL AREA - Underground distribution to individual premises is at
415 volts and 240 volts.
HOUSE - Overhead distribution
to individual houses is at 240 volts.
LIGHT INDUSTRY - Most small factories receive their electricity at 11,000 volts
HEAVY INDUSTRY - Some have direct connections to the transmission at 132,000 volts.
POWER STATION- Generator output at 11,000/20,000 volts is stepped up by transformer to 132, ,000 and 500,000 volts for transmission.
TRANSMISSION - Transmission is mainly at 132, ,000 and 500,000 volts

12. High voltages of 500kV, 275kV, 132kV are used for transmitting electricity over the grid system

13. A transformer in a large sub-station reduces the voltage to 33kV, 22kV,11kV

14. Supplies to rural communities are often reduced from 11kV to domestic voltages (415/240V) by pole mounted transformers.

15. Generation
At power generating station (generating voltage)  11 – 20kV and frequency of 50 Hz
Transform to higher voltage (transmission voltage)  132kV, 275kV and 500kV
Transform to lower voltage (distribution voltage)  33kV or 11kV

16. Worldwide Commercial Energy Production
Since energy is always required to do useful work, the production of energy is one of the most important efforts made by society. Fossil fuels are derived from organic material produced from biomass derived from the process of photosynthesis many millions of years ago. This organic material that was built up in geological deposits over long periods of time are today the primary source of energy for society, accounting for about 79% of all commercial energy in the world. Of the major three fossil fuels (oil, coal and gas), oil is the most important energy source. Oil accounts for 35% of total world energy production. Nuclear makes up 7%. Biomass fuels account for 9.5% of total commercial and energy production. Other renewables such as solar, wind and hydro account for 4.5% of the total. This shows that total renewables (biomass, hydro, etc.) provide 14% of the energy.

17. Coal
The supply of coal in the world is about 10 times greater than oil and gas combined. Much of the coal of the world is located in North and Central America, Asia, and Europe. Coal represents the fossil fuel with the highest reserves relative to the amount presently used. It is likely that coal reserves in the world could supply energy for human use for 200 years at the present consumption rate.
Today, oil is the primary energy source throughout the world, as well as one of the primary contributors to political problems. A single country, Saudi Arabia, has about one quarter of the known supplies of oil in the world, over 10% of recoverable oil reserves are in the volatile Mideastern countries. Interestingly, the nations of the world with the largest amounts of all oil are among the most politically troubled. For instance, Saudi Arabian nationals comprised most of those primarily responsible for the destruction of the World Trade Center in the U.S., the country to which Saudi Arabia sends the largest amount of its oil exports. The countries of Iraq, Iran, Kuwait, and Venezuela also do not rank among the most stable economies or governments in the world and they have much of the earth's oil reserves.
Natural gas, the third most important fossil fuel, has the largest reserves located in the former U.S.S.R. and the Middle East. Natural gas produced from Canada and internally within the United States is one of the main sources of heating fuel for Seattle. Natural gas is extremely efficient to utilize, but very difficult to store and move.

18. Oil
The supply of coal in the world is about 10 times greater than oil and gas combined. Much of the coal of the world is located in North and Central America, Asia, and Europe. Coal represents the fossil fuel with the highest reserves relative to the amount presently used. It is likely that coal reserves in the world could supply energy for human use for 200 years at the present consumption rate.
Today, oil is the primary energy source throughout the world, as well as one of the primary contributors to political problems. A single country, Saudi Arabia, has about one quarter of the known supplies of oil in the world, over 10% of recoverable oil reserves are in the volatile Mideastern countries. Interestingly, the nations of the world with the largest amounts of all oil are among the most politically troubled. For instance, Saudi Arabian nationals comprised most of those primarily responsible for the destruction of the World Trade Center in the U.S., the country to which Saudi Arabia sends the largest amount of its oil exports. The countries of Iraq, Iran, Kuwait, and Venezuela also do not rank among the most stable economies or governments in the world and they have much of the earth's oil reserves.
Natural gas, the third most important fossil fuel, has the largest reserves located in the former U.S.S.R. and the Middle East. Natural gas produced from Canada and internally within the United States is one of the main sources of heating fuel for Seattle. Natural gas is extremely efficient to utilize, but very difficult to store and move.

19. Natural Gas
The supply of coal in the world is about 10 times greater than oil and gas combined. Much of the coal of the world is located in North and Central America, Asia, and Europe. Coal represents the fossil fuel with the highest reserves relative to the amount presently used. It is likely that coal reserves in the world could supply energy for human use for 200 years at the present consumption rate.
Today, oil is the primary energy source throughout the world, as well as one of the primary contributors to political problems. A single country, Saudi Arabia, has about one quarter of the known supplies of oil in the world, over 10% of recoverable oil reserves are in the volatile Mideastern countries. Interestingly, the nations of the world with the largest amounts of all oil are among the most politically troubled. For instance, Saudi Arabian nationals comprised most of those primarily responsible for the destruction of the World Trade Center in the U.S., the country to which Saudi Arabia sends the largest amount of its oil exports. The countries of Iraq, Iran, Kuwait, and Venezuela also do not rank among the most stable economies or governments in the world and they have much of the earth's oil reserves.
Natural gas, the third most important fossil fuel, has the largest reserves located in the former U.S.S.R. and the Middle East. Natural gas produced from Canada and internally within the United States is one of the main sources of heating fuel for Seattle. Natural gas is extremely efficient to utilize, but very difficult to store and move.

20. Hydro-electricity

21. Percent of total electricity generation as hydro-electricity

22. Electricity generation capacity (Ontario, Canada)

23. Hydro-Québec sources of energy supply (2013)
 Other Renewables (2.9%)
 Nuclear (0.2%)
  Thermal (0.1%)

24. Generation Capacity in Malaysia
Generation capacity of major power producer

25. Generation Capacity
Generation Plant Mix

26. TNB Power Stations

27. Hydroelectric Power Plant

28. Under construction

29. Coal-fired Power Plant

30. Combustion Turbine Power Plant

31. Transmission
To ensure the adequacy and reliability of supply that are fundamental needs of modern society.
Provides the link between electricity suppliers and electricity consumers.
Helps reduce energy prices since generation in other regions which are cheaper can be channeled to customers.
Transmission connects regional systems via inter-connectors to encourage cooperation for mutual benefits.

32. Transmission System
Lines/transformers operating at voltages above 100 kV are usually called the transmission system.
Consists of Transmission Line and Sub-stations
Transmission network of 500kV, 275kV and 132kV known as National Grid.

33. Transmission Line Components
Overhead Lines
Cable
Underground Cables
Submarine Cables
Sub-stations

34. Transmission Line Components Tower support structure Cross-arms
Conductors
Insulators
Earth-wires

35. Transmission tower
                                                                                                   
Waist-Type
Tower
Double Circuit
Tower
Guyed-V-Tower

36. Transmission Tower

38. Overhead Line Conductors

39. Insulators

40. Sub-station Size of substation Types of Sub-station
Depends on transformer size
Types of Sub-station
Conventional outdoor
Require bigger space
GIS (gas insulated switchgear)
Less space
Outdoor or indoor

41. Outdoor Sub-station

42. GIS

43. Sub-station Components
Transformer
Circuit Breaker / Switch Gear
Isolator Switches
Busbar
Protection Relay & Control Equipment

44. Power Transformer

45. Circuit Breaker
Spark gap. In event of a lightning strike on the line, the current can jump the gap between that ball and the protrusion on the tank, and make a path to earth. This prevents overloading the breaker.

46. Circuit Breaker

47. Distribution
Lines/transformers operating at voltages below 100 kV are usually called the distribution system.
Part of the electric utility system between the bulk power source and the customer service entrances (loads). 
33kV, 22kV, 11kV, 6.6kV, 415V and 240V

48. Distribution Sub-station
Distribution Intakes (33kV, 22kV)
Distribution Substations (22kV, 11kV, 6.6kV)
Indoor substation
Outdoor substation
Pole mounted substation
Compact substation
Underground substation
Transformer capacity
100kVA, 300kVA, 500kVA, 750kVA and 1000kVA

49. Distribution Intake

50. Indoor Sub-station

51. Underground Sub-station

52. Compact Sub-station

53. Outdoor Sub-station

54. Pole-Mounted Sub-station

55. Distribution Transformer

56. Distribution Circuit Breaker

57. Load Types of Load: Residential Commercial Industrial
Public Transportation
Public Lighting
etc.

58. Residential Load
Consist of lighting, radio, TV, refrigerator, kitchen appliances, washing machine and etc.
Usually, increases in the evening around 6 p.m. and return to a nominal value around 12 p.m.  

59. Commercial Load
Consists of lighting, air-condition and small appliances.
Shops, business premises, schools, universities etc.
The load is fairly constant from 9am until 9pm with the exception of any mid-day break.

60. Industrial Load
Mainly consists of motor load, air conditioner, lighting, welding and furnaces etc. It can be divided into small, medium and large category. The nature of industrial load curve will depend on the number of shifts worked in the industry.

61. Electricity Consumers

62. National Grid System

63. Advantages
Provide multiple paths between various generation sources and loads
Provide for power transfers from one geographic area to another to achieve overall system operating economics
Interconnect the bulk power facilities of individual power station/utilities so that they can better withstand major disturbances

64. Advantages Other advantages: Stability Continuity of service Economy
Load sharing
Continuity of service
Maintenance, breakdown
Economy
Cheap & efficient

65. Interconnection
Peak lopping; imports during peak load (morning) and export during lower demand (evening)
Economic power exchange; export if its price is lower than other and vice versa
Help each other during system emergencies/crisis

66. Load Dispatch Centre (LDC)
Objectives:
Grid system requires a grid controller/operator system.
In order to ensure the supply of energy is safe and reliable.

67. LDC Function Maintains system stability Achieve minimum operating cost
Frequency control
Voltage within limits
Achieve minimum operating cost
Optimize transmission losses
Merit order generation
maintain spinning reserve requirements
co-ordinate generation and transmission maintenance outages
Restoration of supply after system fault

68. Future ASEAN Power Supply Interconnection