Introduction to High Voltage generation

1. Introduction To High Voltage Engineering
• High Voltage Power Systems
• Voltage stresses
• Testing voltages

2. Main Topics
• High Voltage Power Systems
• Voltage stresses
• Testing voltages

3. HIGH VOLTAGE POWER SYSTEMS

4. • Electric Power System: It mainly refers to all installations and plants
provided for the purpose of generating, transmitting and distributing
electricity [Electropedia.org, International Electrotechnical Commission]
High voltage power systems
Generation
• Pearl Street Station was the first commercial power plant in the world.
Based on dc generator, it started generating electricity in 1882 (mainly for
lighting).The station was built by a company headed by Thomas Edison.

5. High voltage power systems
Generation
• The first major a.c. power station was commissioned in 1890 at Deptford,
supplying power to central London over a distance of 14km at 10kV
• At this time, it was realized that an interconnected high voltage power
system is the best solution (economically, and technically)
• The frequency of the ac voltage is today 50Hz or 60Hz
• IEC 60038 classify the voltages as
• Low voltage: up to 1000V
• Medium voltage: between 1kV and 35kV
• High voltage: between 35kV and 230kV
• Extra high voltage: above 230kV

6. High voltage power systems
Generation
The following lists some major a.c. transmission systems in chronological
order of their installations
Year Voltage City Country
1890 10kV Deptford England
1907 50kV Stadtwerke
Munchen
Germany
1912 110kV Lauchhammer Germany
1926 220kV N. Pennsylvaia USA
1952 380kV HarsPranget Sweden
1965 735kV Manicouagan Canada
2003 500kV Three Gorges China
The increase of the voltage level is a result of growing demand for electrical
energy and development of large hydro power plants

7. High voltage power systems
Generation
Three Gorges Power Plant: more than $45 billion project (22.5GW). 32 units.
Francis turbines
Synchronous
Generator

8. High voltage does not only include generators, transformers, and
transmission line. Flexible AC Transmission System to enhance
controlability and stability of the power systems
High voltage power systems
FACTS
Canada, 735kV

9. High Voltage Direct Current transmission
by overhead lines, submarines cables
provides an attractive alternative for power
transfer.
In many cases, HVDC links are justified
based on a combination of technical, and
economic advantages.
DolWin (2017)
320 kVdc, 45-km long DC sea cable
and 90-km long land cable to an
HVDC onshore station at the grid
connection point
High voltage power systems
HVDC

10. High voltage power systems
HVDC
Year Voltage
1950 100kV
1960 100kV
1970 500kV
1980
1990 600kV
2000 500kV
The following lists some major a d.c. systems in chronological order of their
installations
The are a lot of HVDC projects in the world. Some of them are planned for
2025. Current trends indicate that d.c. Voltage levels will not increase
dramatically in the near future.

11. VOLTAGE STRESSES

12. Normal operating voltage does not generally stress the power system’s
insulation except in special cases (e.g. pollution conditions). The operating
voltages is used to determine the sizing of the insulation system
Voltage Stresses
Generality
The voltage stresses on power systems can come from:
 External overvoltages (e.g. lightning discharges)
 Internal overvoltages (line energization, Load rejection, fault
initiation and clearing, variation of the load, reactor switching,
etc.)

13. TESTING VOLTAGES

14. Power system equipments must withstand not only the rated voltage but also
the overvoltages. H.V. equipments are tested after their manufacturing.
Testing Voltages
The magnitude and type of test voltage, the test procedure, are generally set by
national and international norms (IEC, IEEE, etc.)
1- Testing with power frequency voltages
The equipment is subjected to 1 minute test under 50Hz r 60Hz depending
upon the country. The test voltage is set at a level higher than the expected
working voltage to be able to simulate the stresses likely to be encountered
over the years of service (for indoor and outdoor equipments)

15. Testing Voltages
2- Testing with lightning impulse voltages
Lightning strokes may induce overvoltage of thousand kilovolts. The standard
impulse voltage has been accepted as an impulse that reaches its peak value
in 1.2μs and then decreases slowly (in about 50μs) to half its peak value
3- Testing with switching impulses (transient overvoltages, etc.)
4- D.C. voltages (for HVDC equipments, a.c. cables .)