Introduction to Power System

Dr. Jing Wang

Head of Institute of Power Electronic and Electric

Drive

kmhelen@sina.com.cn

II What is power system? II What is power system?

I Where does electricity come from?I Where does electricity come from?

III Do voltage and frequency matter?

III Do voltage and frequency matter?

I Where does electricity come from?

1791 -1867

Michael Faraday

3

magnet

Coil

electric current

4

magnet

coil

electric current

Electric current is induced whether a magnet moves near coil or the coil moves in a magnet (relative movement ).

5

6

How can we keep the coil

rotating like that?

How can we keep the coil

rotating like that?

7

Types of Power Plants

Thermal

Nuclear

Hydroelectric

Wind

Solar-PV

Biomass

Geothermal

……

Conventional SourcesConventional Sources

Non Conventional SourcesNon Conventional Sources

Thermal Power Plant

99

Turbines

10

Steam turbine generator set

RotorStator

11

1212

Types of Power Plants

Thermal

Nuclear

Hydroelectric

Wind

Solar-PV

Biomass

Geothermal

……

Nuclear Power Plant

14

15

Types of Power Plants

Thermal

Nuclear

Hydroelectric

Wind

Solar-PV

Biomass

Geothermal

……

Hydroelectric Power Plant

17

Hydroturbine rotor

RotorStator

18

Hoover

Itaipu

Dams

19

1. On electricity, power systems and smart grids

Grid 101 - The Power Grid Explained ： https://www.youtube.com/watch?v=5wF03-bqyJo

Where energy comes from ： https://www.youtube.com/watch?v=__zB80Saglk

Energy 101: Electricity Generation ： https://www.youtube.com/watch?v=20Vb6hlLQSg

What Is the Smart Grid? ： https://www.youtube.com/watch?v=JwRTpWZReJk

2. On Generators

Nuclear Power: How Nuclear Power Plants Work ： https://www.youtube.com/watch?v=_UwexvaCMWA

Thermal power plant ： https://www.youtube.com/watch?v=rEJKiUYjW1E

Hydro Power ： https://www.youtube.com/watch?v=rnPEtwQtmGQ

https://www.youtube.com/watch?v=tpigNNTQix8&list=PLACD8E92715335CB2&index=8

Pumped Storage hydropower plant ： https://www.youtube.com/watch?v=Tt_NtTOJEE8

Wind Power: How Wind Turbines Generate Electricity ： https://www.youtube.com/watch?v=mrnul6ixX90

Wind Turbines ： https://www.youtube.com/watch?v=EYYHfMCw-FI&index=3&list=PLACD8E92715335CB2

Solar Power: https://www.youtube.com/watch?v=0elhIcPVtKE

https://www.youtube.com/watch?v=0elhIcPVtKE&list=PLACD8E92715335CB2&index=16

1. On electricity, power systems and smart grids

Grid 101 - The Power Grid Explained ： https://www.youtube.com/watch?v=5wF03-bqyJo

Where energy comes from ： https://www.youtube.com/watch?v=__zB80Saglk

Energy 101: Electricity Generation ： https://www.youtube.com/watch?v=20Vb6hlLQSg

What Is the Smart Grid? ： https://www.youtube.com/watch?v=JwRTpWZReJk

2. On Generators

Nuclear Power: How Nuclear Power Plants Work ： https://www.youtube.com/watch?v=_UwexvaCMWA

Thermal power plant ： https://www.youtube.com/watch?v=rEJKiUYjW1E

Hydro Power ： https://www.youtube.com/watch?v=rnPEtwQtmGQ

https://www.youtube.com/watch?v=tpigNNTQix8&list=PLACD8E92715335CB2&index=8

Pumped Storage hydropower plant ： https://www.youtube.com/watch?v=Tt_NtTOJEE8

Wind Power: How Wind Turbines Generate Electricity ： https://www.youtube.com/watch?v=mrnul6ixX90

Wind Turbines ： https://www.youtube.com/watch?v=EYYHfMCw-FI&index=3&list=PLACD8E92715335CB2

Solar Power: https://www.youtube.com/watch?v=0elhIcPVtKE

https://www.youtube.com/watch?v=0elhIcPVtKE&list=PLACD8E92715335CB2&index=16

Online Materials

20

II What is power system? II What is power system?

I Where does electricity come from?I Where does electricity come from?

III Do voltage and frequency matter?

III Do voltage and frequency matter?

II What is power system?

22

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam Turbine

23

24

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam TurbineStep-up Transformer

Transformers

PURPOSE: to change the voltage• increase = “step-up”

• decrease = “step-down”

Often run hot, must be cooled, prone to explode.• oil inside

• cooling fins and fans

• blast walls

Why need to change Voltages?

Why is that so?

Why need to change Voltages?

Why is that so?

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Electrical Substation

2626

27

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G~

M~

M~

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| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam TurbineStep-up Transformer

Buses

Buses uninsulated electrical conductors large cross-section = low resistance must be far from ground and other components to

avoid arcing

28

G~

G~

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G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam TurbineStep-up Transformer

Buses

Transmission lines

29

30

31

32

33

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G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam TurbineStep-up Transformer

Buses

Transmission lines

Step-down Transformer

34

Distribution lines

35

Step-down transformer

35

To your house...

36

37

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Hydroturbine

Power Plants

Generator

Steam TurbineStep-up Transformer

Buses

Transmission lines

Step-down Transformer

Consumers

38

a network of electrical components used to generate, transmit,

distribute and consume electric power

generate transmit

distribute consume

Electrical power system

39

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Electrical power system

40

Power Grid

an interconnected network for transmitting and distributing

electricity from suppliers to consumers

transmission distribution

41

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G~

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G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

Power Grid = Electrical power system – generators - consumers

Transmission System

Distribution System

42

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

43

44

G~

G~

G~

G~

G~

G~

G~

G~

M~

M~

M~

| |

Damboiler

Heat supple network

boiler

boiler

boiler

220kV

110kV

10kV0.38kV

10.5kV

50Hz60Hz

45

II What is power system? II What is power system?

I Where does electricity come from?I Where does electricity come from?

III Do voltage and frequency matter?

III Do voltage and frequency matter?

III Do voltage and frequency matter?

1. What is the history of voltages and frequencies?

2. What are voltage levels? Why are they choosed as standards?

3. What kinds of frequencies are chosen as base frequency? Why is that so ?

4. Why are High Voltages Used to transmit power energy? Why is that so?

5. What conditions do we need to use AC or DC systems ?

1. What is the history of voltages and frequencies?

2. What are voltage levels? Why are they choosed as standards?

3. What kinds of frequencies are chosen as base frequency? Why is that so ?

4. Why are High Voltages Used to transmit power energy? Why is that so?

5. What conditions do we need to use AC or DC systems ?

Questions

47

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