Introduction to Power System Dr. Jing Wang Head of Institute of Power Electronic and Electric Drive

II What is power system? I Where does electricity come from? III Do voltage and frequency matter? I Where does electricity come from?

Michael Faraday 3

August 29, 1831 Changing magnetic field in a loop induced voltage(current). 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

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How can we keep the coil rotating like that? 7

Types of Power Plants Thermal Nuclear Hydroelectric Wind Solar-PV Biomass Geothermal …… Conventional Sources Non Conventional Sources

Thermal Power Plant 9 9

Turbines 10

Steam turbine generator set Rotor Stator 11

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Types of Power Plants Thermal Nuclear Hydroelectric Wind Solar-PV Biomass Geothermal ……

Nuclear Power Plant 14

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Types of Power Plants Thermal Nuclear Hydroelectric Wind Solar-PV Biomass Geothermal ……

Hydroelectric Power Plant 17

Hydroturbine rotor Rotor Stator 18

Hoover Itaipu Dams 19

1. On electricity, power systems and smart grids Grid The Power Grid Explained ： Where energy comes from ： Energy 101: Electricity Generation ： What Is the Smart Grid? ： On Generators Nuclear Power: How Nuclear Power Plants Work ： Thermal power plant ： Hydro Power ： Pumped Storage hydropower plant ： Wind Power: How Wind Turbines Generate Electricity ： Wind Turbines ： Solar Power: Online Materials 20

II What is power system? I Where does electricity come from? III Do voltage and frequency matter? II What is power system?

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G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine 23

24 G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine Step-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? 25

Electrical Substation 26

27 G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine Step-up Transformer Buses

 uninsulated electrical conductors  large cross-section = low resistance  must be far from ground and other components to avoid arcing 28

G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine Step-up Transformer Buses Transmission lines 29

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G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine Step-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~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Hydroturbine Power Plants Generator Steam Turbine Step-up Transformer Buses Transmission lines Step-down Transformer Consumers

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a network of electrical components used to generate, transmit, distribute and consume electric power generatetransmit distributeconsume Electrical power system 39

G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Electrical power system 40

Power Grid an interconnected network for transmitting and distributing electricity from suppliers to consumers transmission distribution 41

G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler Power Grid = Electrical power system – generators - consumers Transmission System Distribution System 42

G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler 43

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G~ G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ G~G~ M~M~ M~M~ M~M~ | Dam boiler Heat supple network boiler 220kV 110kV 10kV 0.38kV 10.5kV 50Hz 60Hz 45

II What is power system? I Where does electricity come from? 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 ? Questions 47

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