UHV 1200 kV AC Transmission

UHV 1200 kV AC Transmission GRIDTECH 2007

Power Transmission and Distribution

H. Huang, D.Kumar, V. Ramaswami, D. Retzmann

Technical Alternatives for Bulk Power Transmission HVAC Systems ¾ 500 kV conventional as also series compensated ¾ 750 kV conventional as also series compensated ¾ 1200 kV conventional as also series compensated

HVDC Systems ¾ ± 500 kV bipole ¾ ± 550 kV bipole ¾ ± 600 kV bipole ¾ ± 800 kV bipole

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Development of Voltages Levels for AC Power Transmission Voltage 1400 6 1200 kV 1000

5

800 600 400

2 200

4

3

experimental in commercial use

1

1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

2000

Year

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EHV and UHV AC Systems – at Present

1000 kV Line: SIL = 4 GW Transmission of 6-10 GW is feasible Page 4

Voltage Levels of 735 kV to 765 kV AC have been introduced in the following Countries: Canada, Brazil, Russia (USSR), South Africa, South Korea, U.S.A. and Venezuela UHV Transmission Lines (1000 kV and above) have been built in Russia and Japan Ekibastuz – Kokchetav (500 km) Kokchetav – Kustanay (400 km) Minami – Niigata / Nishi – Gunma (200 km) Kita – Tochigi / Minami – Iwaki (250 km) However, today these UHV Transmission Lines are operated at 500 kV Dec.-06

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Product-Portfolio Non-Switching HV-Products Coil Products

Bushings

Current and Voltage Transformer

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Line Traps

Arrester


Product Range Live-Tank High-Voltage Circuit-Breakers

Rated short-circuit breaking current [kA] 80 3AT4/5 63 3AT2/3 50 40 31.5 25 0

3AP1 FG 72.5

123

3AP1 FI 145

170

245

3AP2 FI 300

362

420

550

800 1000 Rated voltage [kV]

¾ The existing C.B. product range is covering 800 kV Scaling up to 1000 kV is possible Page 6

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High-Voltage Circuit-Breaker 3AT4/ 5 EI up to 1000 kV

¾ EHVAC C.B. is using proven design and can be scaled up from existing 550/800 kV type to 1000 kV ¾ R&D program may be decided for 1000kV according to specification ¾ Requirements for short circuit current and higher altitudes above sea-level have to be specified ¾ Ambient and environmental conditions have to be considered

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1000 kV EHVAC Double Break Disconnectors from existing range of 800kV..... Technical Technical Data Data Rated Rated voltage voltage Rated lightning Rated lightning impulse impulse withstand withstand voltage voltage (1,2/50 (1,2/50µs) µs) Across the isolating distance Across the isolating distance Rated Rated switching switching impulse impulse withstand withstand voltage voltage Across Across the the isolating isolating distance distance Rated Rated current current Rated Rated short-time short-time current current

800 800 kV kV 2100 2100 kV kV 2235 kV 2235 kV 1300 1300 1725 1725 4000 4000 63 63

kV kV kV kV A A kA kA

...to 1000kV design: Up-scaling will cover the requirements on creepage distance & mechanical strength of porcelain Page 8

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1200 kV Power Transformer Prototype tested in 1972 ¾ EHVAC Transformer using proven design can be scaled up from existing 800 kV type ¾ R&D program may be decided for 1000kV according to specification ¾ Dielectric specification and transport dimensions determine R&D cost and time ¾ Test facilities are an open issue

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Recent Activities for UHV Example AC Test Transformer 1200 kV

Transformer & Reactor Bushings: Type OTA; Trench UK *, Oil-Paper Technology Production: Hebburn/UK, MWB Shanghai/China Design for 1200 kV Transformer is available Reference: Henjang / China

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**now nowSiemens Siemens Dec.-06

Protected Creepage Distance: 10.5 m PTD H 1T


Development of UVH AC Transmission

Bundle of 8 Conductors

Rated Voltage: 1000 kV Maximum Operation Voltage: 1100 kV

Source:

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1000 Dec.-06kV Test Line PTD H in 1T China


Road Map for UVH AC Transmission in China 1000 kV Pilot Project Shaanbei

Jindongnan

Project Highlights: Totally 650km Length Including two UHV-AC Substations and one Switchgear Station

Nanyang

Source:

Jingmen Page 12

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Wuhan Power Transmission and Distribution

Specific Issues – for UHV AC The AC Measurements for UHV Capacitive Voltage Divider Type TEHMF Trench Canada * Production: Toronto und Shanghai In Service up to 800 kV Scaling-up for 1100 kV is no Problem

**now nowSiemens Siemens SF6 insulated CT and PT – Design is well proven Type SAS, SVS; Trench Germany * Production: Bamberg and Shanghai In Service up to 800 kV Scaling-up for 1100 kV is no Problem Page 13

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Tower Configurations 19 m

15.5 m

48 m

92 m

16.5 m

50 m

44 m

71 m

108 m

16 m

Line conductors

Kita – Iwaki

Ekibastuz – Kokchetav

8 x 31,5 mm ACSR

8 x 24.1 mm AS-330

6,5

8

Air gap clearance phase-earth [m] Page 14

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Bundle Design and Tower Configuration Voltage Phase conductor wire Outer diameter Sub conductor spacing

1000 kV 8 x 403/52 ACSR 27.7 mm 400 mm

44 m

Ø = 1.07 m

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Calculation of Overhead Line Characteristic

Resistance Reactance Capacitance Surge impedance Surge impedance load Charging power Maximum surface gradient

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0.0107 Ω/km 0.267 Ω/km 14.15 nF/km 245 Ω 4080 MW 4.45 MVAr/km 14.7 kV/cm


Electric Field Strength

50 m

5 kV/ m - 10 kV/ m 10 kV/ m - 20 kV/ m 20 kV/ m - 50 kV/ m 50 kV/ m - 100 kV/ m > 100 kV/ m

0m -50 m

0m

50 m

Sectional view of the transmission line vertical to the line axis

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Reactive Power Demand of Overhead Lines as a Function of Load Reactive Power [MVAr/100 km] 600

1000 kV 400

750 kV 200

500 kV 380 kV 220 kV

0.5

0

1

1.5

P/SIL -200

-400

-600

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1000 kV AC Transmission Line No-Load Operation V1 = 100 %

V2

QC

Need of shunt compensation

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L (km)

QC (Mvar)

V2/V1

250

1,133

1.04

500

2,417

1.17

750

4,169

1.50

1000

7,670

2.45


Transmission System with Shunt and Series Compensation

P SIL

Θ Θ0 Kp = 0

Kp = Degree of shunt comp.

Kp = 0

Kp (ind)= 0.5 Ks = Degree of series comp.

Ks

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Load capability of transmission system referred to the surge impedance load Dec.-06

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Ks Transmission angle as a function of degree of compensation


Load Capability of Transmission System Referred to Surge Impedance Load (SIL) P SIL

Kp (ind.)

Kp (cap.)

Kp = Degree of shunt compensation Page 21

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Power Frequency Overvoltage During 1-phase Auto-reclosing 5

V [p.u.] 4,5

Z0/Z1=2,0 Z0/Z1=1,0 degree of compensation

4 3,5 3 2,5 2 1,5 1 0,5 0 0%

10%

20%

30%

40%

50%

60%

70%

80%

90% 100% 110% 120% 130%

degree of shunt compensation

Power frequency overvoltage of disconnected phase during 1-phase auto-reclosing for different Z0/Z1 ratios of shunt reactor Page 22

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Ultra HVAC System > 1000 kV

Early research works on feasibility of 1100 kV system by AEP, Furnas and some manufacturers.

Further research works on 1000 kV by ENEL-CESI in Italy

1100 kV TEPCO line in Japan ( 140 km)

1100 kV line in Russia operated at 500 kV as reported

1000 kV demonstration line with 3 substations are currently under development in China

Conclusion: UHVAC technology is technically feasible. R&D works are needed on the equipment side

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