13 October 2015 Delft University of Technology Electrical Power System Essentials ET2105 Electrical Power System Essentials Prof. Lou van der Sluis The Transmission of Electric Energy

2 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Introduction (1) Transmission and Distribution Advantages of interconnected systems Better reliability Smaller frequency deviations Better overall system efficiency Facilitates power exchange Disadvantages of interconnected systems Limitations to interconnection transport capacity Power losses because of energy exchange Unwanted parallel power flows More complex system operation

3 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Introduction (2) Rated voltage for AC – power system

4 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Introduction (3) Voltage levels in the Dutch Power System

5 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Dutch High-Voltage Network Introduction (4)

6 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Network Structures Radial structureLoop structureMulti-loop structure

7 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Substations (1) Open-air substation Courtesy of TenneT TSO B.V.

8 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Substations (2) High-Voltage Circuit Breakers and Pantograph Disconnector Courtesy of TenneT TSO B.V.

9 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Substations (3) SF 6 -insulated substation Courtesy of Eaton Holec

10 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Substations (4) Bus system Single bus system Double bus system

11 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Transformer The ideal transformer

12 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Transformer Model (1) Not ideal Permeability is not infinity Finite self inductance Leakage flux Winding losses (copper losses) Core losses Hysteresis Eddy-current losses

13 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Transformer Model (2) Copper losses Leakage reactance Iron losses (core) Magnetizing susceptance Efficiency = P out / P in = 1 – P loss / P in

14 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Three-Phase Transformer (1) Three single-phase transformers Three phase transformer Complex turns ratio 1 : a*e j  Amplitude Phase shift: multiple of 30°

15 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Three-Phase Transformer (2) Single-phase equivalent

16 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Three-Phase Transformer (3) Out of the tank Courtesy of TenneT TSO B.V.

17 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Yy-4 Transformer

18 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Yd-11 Transformer

19 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials The Magnetization Current The magnetization current contains a third harmonic

20 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Overhead Transmission Lines (1) 380 kV River crossing Courtesy of TenneT TSO B.V.

21 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Overhead Transmission Lines (2) The power carriers in the Dutch power system

22 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Overhead Transmission Lines (3) 150kV transmission line tower

23 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transmission Line Conductors (1) Material Al Cu ACSR (Aluminum Conductor Steel Reinforced)

24 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transmission Line Conductors (2) Courtesy of TenneT TSO B.V.

25 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transmission Line Conductors (3) Advantages and disadvantages of bundled conductors

26 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Galloping Lines Counter measures

27 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Shield Wires

28 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transposition (1) Unbalanced system Solution: transposition

29 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transposition (2)

30 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials High-Voltage Cable Courtesy of Prysmian Cable Holding B.V. 6/10 kV cable220/380 kV cable

31 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Transmission of Power Poynting Vector: S = E x H V H H H E E E S S S E S S H HE S S

32 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Conductor Modeling L: H-field C: E-field R: Ohmic losses G: Insulator and corona losses RL GC

33 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Line / Cable Line, 150 kV R=  /km X L =  /km C= 7.7 nF/km S th = 130 MVA Cable, 150 kV R = 0.12  /km X L =  /km C = 210 nF/km S th = 135 MVA

34 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials 1 km Line / Cable Line, 132 kV R =  X L = j0.40  X C = -j350 k  I = 450 A Cable, 400 kV R = 9 m  L = 0.4 mH C = 0.38 µF I = 1.9 kA

35 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Line Models Short (<80 km) Medium (80 km..240 km) Long (>240 km) VRVR IRIR ISIS VSVS Z IRIR ISIS VSVS Y/2 VRVR Z IRIR ISIS VSVS VRVR  /km H/km F/km

36 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Short Line VRVR IRIR ISIS VSVS R+jX Vr Vs jIrX Ir IrR Vr Vs jIrX Ir IrR Vr Vs jIrX Ir IrR

37 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Series-Compensation Z = R + jX = R + j (  L - 1/  C) Hydro-Quebec / 735 kV

38 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Long Line: Distributed Elements zxzx yxyx V(x)V(x) xx V(x+  x) I(x)I(x) I(x+  x)

39 3. The Transmission of Electric Energy | 39 ET2105 Electrical Power System Essentials Equivalent Circuits of Lines Short Medium Long VRVR IRIR ISIS VSVS Z IRIR ISIS VSVS Z Y/ 2 VRVR IRIR ISIS VSVS Z' Y'/ 2 VRVR