Without proper planning and careful addition of new technologies and facilities, keeping power on becomes a game of chance. To meet growing load demands and maintain reliability, utilities across the globe are constructing dc links, upgrading lines and interconnecting systems. Technological advances and existing technologies are being used to not only increase efficiency and reliability, but to give the electric power user the best service at the best price. Following is a worldwide sampling of planned activities in the field of power delivery.
NORWAY: HVDC Links to Continental Europe The Norwegian power system is part of the NORDEL system that is connected to the UCPTE network by three HVDC links (1000-MW capacity). Power exchange agreements between Norwegian and European authorities are in place to add three additional HVDC links, each 600-800 MW capacity, to be commissioned in 2001, 2002 and 2003, respectively.
PERU: Linking Independent Power Project with a Load Center As part of a major independent power project being developed in Peru, a 400-km (250-mile), 220-kV line is being constructed across the Andes Mountains in South America. The line originates at the new Aguaytia generating station in eastern Peru and extends to the Paramonga Neuva Substation near Pativilca in western Peru.
The line will interconnect with the Peruvian electric utilities of Electrocentro at the existing Tingo Maria Substation, located approximately 75 km (47 miles) from Aguaytia, and Etecen at the Paramonga Substation.
Ground breaking for the project took place in October 1996. Completion is scheduled for mid-1998.
ITALY-GREECE: 400-kV HVDC Interconnection To further develop the trans-European networks, an interconnection is planned for the 380-kV ac networks of Italy and Greece. The proposed 400-kV HVDC submarine cable link across the Channel of Otranto will have a route length of 160 km (100 miles). All aspects of the design, specification and manufacture are complete. The project will begin once the Greek and Italian authorities have granted permission for construction.
MIDDLE EAST: Multi-Country Interconnected Power System A feasibility study is looking into interconnecting the power systems of Egypt, Jordan, Syria, Iraq and Turkey. The recommended interconnection would be a 400-kV system about 630 km (394 miles) long. The interconnection would use existing circuits, including a 500-kV line between Egypt and Jordan.
The Egypt-Jordan interconnection is currently under construction. It includes a 290-km (181-mile), 500-kV line crossing Sinai from the existing 500-kV system to Taba, Egypt where a 750-MVA, 500/400-kV substation and a 400-kV submarine cable will interconnect with the 400-kV system in Jordan. The project is scheduled for commissioning in 1997.
The 220-kV systems in Egypt and Libya are being extended along the Mediterranean Sea towards their international boundaries to provide an interconnection and power exchange facility.
Two single-circuit, 210-km (130-mile), 225-kV lines are planned to interconnect the power systems of Libya and Tunisia. Commissioning is set for 1997.
MOROCCO: Interconnection with Spain A new electrical connection has been constructed between Morocco and Spain. The link comprises a 400-kV, 25-km (15.6-mile) ac submarine cable that crosses the Straits of Gibraltar. The link provides Morocco with an interconnection with Europe.
INDIA: National Power Grid Formation The government of India is planning to implement synchronous operation of the Indian National Power Grid by interconnecting all regions of the country. Before doing so, an interim stage is planned to provide inter-regional links. The following HVDC back-to-back links have been built or are scheduled for completion by 2000: - 500 MW link between the northern region (Mau) and the eastern region (Biharshariff). - 500 MW link between the northern region (Singrauli) and the western region (Vindhyachal). - 500 MW link between the eastern region (Jeypore) and the southern region (Gazuwaka). - 1000 MW link between the western region (Chandrapur) and the southern region (Ramagundam).
SOUTH KOREA: Plans Set for 765-kV Lines The Korea Electric Power Co. (KEPCO) plans to construct bulk transmission circuits from sites of load generation on the east and west coasts to the load center in Seoul, South Korea. The transmission lines are planned as 765-kV double-circuit lines with route lengths of 170 km (106 miles) west and 160 km (100 miles) east. The lines will be in commission by the end of 1998.
JAPAN: 1000-kV Overhead and 500-kV Submarine Cable The Tokyo Electric Power Co., Inc. (TEP) is constructing a 1000-kV transmission system to provide efficient bulk power transfer and, thereby, optimize use of the limited number of line routes available in the region. Low-noise conductors were developed for the 110 km (69 mile) long, 1000-kV, Kita-Tochigi Trunk line that was commissioned in 1996.
TEP's system development plan includes constructing the 1000-kV, 130-km (81-mile) Minami-Iwaki trunk line scheduled for commissioning in early 1999.
A planned 500-kV dc oil-filled submarine cable will establish a 2800-MW dc link between Honshu and Shikoku islands. The 50-km (31-mile) link, comprising four cables (two positive and two negative), initially will operate at + 250 kV. It is scheduled for commissioning in the year 2000.
AFRICA: Sub Equatorial Interconnections Begun Construction has started on a 270-km (169-mile) interconnector from Mozambique to Zimbabwe to transport 500 MW generated at the Cohora Bassa hydro power station. This 400-kV ac interconnector will initially operate at 330 kV.
CHINA: System Interconnection Developments Major regional system intertie projects are planned for China through the year 2010. Three of the key projects include: - Construction of two 500-kV lines, 700-km (438-miles) long connecting north China to east China. These ac circuits will connect to Yangcheng power plant due to come on-line in 2000. - Adding a new 500-kV dc line connecting northwest China to Sichuan. The new line will be 600 km (375 miles) long. - The Three-Gorges hydropower station (18,300 MW capacity), to be commissioned between 2004-2010, will require new transmission systems to supply east China, central China and Sichuan.
POLAND: Integrating with the European Electricity Sector The Polish Power Grid Co. (PPGE) is upgrading transmission lines with-in its borders and interconnecting to neighboring grids. The PPGE is replacing the existing Miculowa-Hagen-werder 220-kV line with a 400-kV line and plans to bundle a double-circuit 400-kV line for the Nowa Sol-Eisenhuttenstadt region.
A 230-km (144-mile), 450-kV dc link is scheduled for construction between the Polish and Swedish power systems between 1999-2003.
Construction of the Krosno (Poland) and Lemesany (Slovakia) 400-kV line began in 1996.
DENMARK: Modernizing a High-Voltage System Construction of 450 km (281 miles) of a 400-kV line is planned for the country of Denmark. The 400-kV network will provide system stability, increase system capacity and eliminate a number of low-voltage lines. More specifically, 2000 km (1250 miles) of 60/50-kV lines and 700 km (438 miles) of 150/132-kV lines will be removed.
EUROPE: Eastern-Western High-Power Network Studies The viability of constructing in Europe a 500-kV dc, 1800-km (1125-mile) link with a 4000-MW capacity is being studied. The studies are being supported by Russia, Belarus, Poland and Germany. The countries are hoping for commissioning of the link early next century.
