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First 800-kV High-Voltage Direct-Current Link in China Now Fully Operational; Transmission of Hydro Power to Pearl River Delta

Siemens Energy and the utility China Southern Power Grid have put into operation the second pole of a world-record high-voltage direct-current (HVDC) system. The transmission capacity has now been doubled to 5,000 megawatts (MW). With one pole operating at plus 800 kilovolts (kV) and the other at minus 800 kV, the voltage difference between the poles reaches the world record of 1,600 kV DC.

In December 2009, the link had also set the world record for first DC operation ever at a voltage level of 800 kV DC. Since that date, Pole 1 has operated at nominal power of 2500 MW without any interruptions.

This has been an ambitious project including ground-breaking product developments and we have ultimately even managed to complete it ahead of schedule. With DC systems operating at ultra high-voltage levels we now have the transmission technology of the future in our portfolio. This technology is ideal for transporting clean, renewable power over thousands of kilometers to consumers—with nearly zero losses.

—Udo Niehage, CEO of the Power Transmission Division of Siemens Energy

The 5,000 MW of CO2-free power is produced by several hydro power plants in the remote Yunnan Province and will be transported with minimal losses to the rapidly growing industrial region in the Pearl River delta in Guangdong Province with its megacities Guangzhou and Shenzhen.

This will reduce annual CO2 emissions by more than 30 megatons compared with equivalent fossil-fueled power plants in the power grid of Guangdong Province.

The Yunnan-Guangdong UHVDC system covers a transmission distance close to 1,500 kilometers (932 miles). The new ultra-high voltage level of 800 kV offers global transmission operators economical low-loss bulk power transmission over even longer distances. Distances of 3,000 kilometers (1,864 miles) and even more are feasible now with UHVDC technology of this kind: At a transmission capacity of 5000 MW losses are as low as around 2% per 1000 kilometers, plus less than 1.5% losses for both converter stations at the sending and receiving end of the transmission line.

Together with its Chinese partners, Siemens designed the entire HVDC system for the Yunnan-Guangdong project and developed and supplied the core components for this technology, which included 800-kV and 600-kV converter transformers, DC filters and all 800-kV direct-current components.

Energy-efficient HVDC systems for highly reliable, low-loss transmission of large amounts of power over long distances are part of Siemens’ Environmental Portfolio. In fiscal 2009, Siemens generated revenue of €23 billion with products and solutions from its Environmental Portfolio. During 2009, Siemens customers worldwide were able to reduce their carbon dioxide (CO2) emissions by a total of 210 million tons with products and solutions from the Siemens Environmental Portfolio.

Comments

Dave R

Impressive. Isn't China working on more large scale hydro plants as well?

That type of transmission line will also be useful for transporting energy from West China's planned wind and solar generation plants.

mahonj

These could be used for the European "supergrid" that is proposed (by the wind companies) for moving wind power all around Europe, from Ireland to Spain etc.
It could also be used to move Saharan solar energy from Africa to Europe.
I bet Siemens would love that.

HarveyD

Those very high DC voltage transmission lines have a bright future in many places. It is surprising to see China in the forefront.

mahonj: China, with its much larger population, has a higher potential for future power grids. Not having to deal with 27 different countries (+ Africa) simplifies and accelerates the decision making process.

Henry Gibson

One of the first large scale Direct Current transmission links for power was from the Columbia River in Washington-Oregon to Los Angeles many years ago.

California ought to stop pretending that it is using renewable energy in its state by developing its own source to replace the Columbia river power and also the AC transmission of Colorado river power into its state.

What this article does not mention is that with direct current, buried cables can be used to transmit the power with high efficiency. Several such buried and underwater cables already are serving Europe, and Long Island gets some power from a small such cross Sound system.

The future of electrical grids can be buried high efficiency cables all the way to the home. Semiconductors allow the required conversions to lower voltages to be done with sufficient efficiency. The grid is then also an energy storage device itself and much more reliable because it is buried. Every house might then have an inverter to provide standard power from 600 to 3000 volts direct current. High voltage batteries such as those made and sold by NGK can be added simply to the system.

Direct current high voltage transmission lines require less space, but buried high voltage cables require far less space. The cost of the insulation is balanced some what using lower cost conductive metal, by needing no towers and even much less land.

Wind machines and other generators can just add power to the system without any concern about windspeed and frequency control. The cheapest way to store solar energy is just not to burn fossil fuels whilst the sun is shining, and any number of large engines or turbines can be brought up to speed to feed the direct current grid before the grid looses too much energy for the inverters to function. The grid becomes the ultimate super-capacitor and also has batteries on it.

Low cost sodium instead of expensive copper or aluminum can be used in most such cables. Magnesium is another option to copper or aluminum. The thick plastic coating needed for insulation prevents all corrosion.

All motorways and roads are available for such buried cables.

Mobile converter stations should be set up in the center of a country and move outward as the million volt cables are buried in the road ways. Lower voltage systems extend from city to city and yet lower voltages, from 1000 to 30000 volts are in the cities and about 300 to 600 volts to each home inverter. A computer desktop power supply can work directly from 300 volts direct current in most cases.

Semiconductors now can allow all grid links to be underground and efficient. Nuclear power would then be in a position to supply all energy needed to a home. Heating would be by heatpump. ..HG..

Herm Perez

You are a dreamer Henry.

One advantage of using the roads to distribute the power is that it would simplify electrifying the roads for BEVs.

So how much does it cost to run one of these lines under the ground?

Engineer-Poet

Underground HV lines need heavy insulation and have issues with both thermal cycling and heat dissipation. This makes them very expensive compared to the free insulating and heat-transfer services provided by air.

Henry is a crank (sodium? in wet underground environments?!). I think ToppaTom dictates his comments into a speech-to-text system, because his trolls are perfectly spelled but often have homonym errors. Neither should be posting here.

Henry Gibson

There are sodium cables that were made decades ago still in operation. The plastic electrical insulation is more than thick enough to protect the sodium from water. The cheap sodium allows larger cables to be used underground and avoid the production of some of the heat.

People can read about the underground and underwater direct current cables that the ABB and other countries have been making and building for about fifty years. A new one was just put into service between Norway and the Netherlands under the North sea about two years ago. It runs only at about 400,000 volts and it is mostly used to send cheap hydropower from Norway to Holland but if there is a drought power can be shipped to Norway even from the Nuclear reactors of France. There are several high voltage power cables from Scandinavia to Europe.

The ABB website is interesting especially for the power cables run from the coast of Norway to an oil production platform to provide power for pumping natural gas through undersea pipes to Europe.

HG is definately a crank, but he also knows quite a bit about power generation and transmisssion and computers and CANDU heavy water reactors and the fact that sodium cables were made and used years ago when copper was very high priced and sodium was very cheap because it was still being used to make leaded gasoline.

Four or five inches thick of high quality polyethylene can withstand a few hundred thousand volts, so a high voltage DC cable can be run underneath a bicycle path if a wider road is not available. The much lower cost and fewer delays for a buried cable route can easily make up for the cost of the cable. Large volume mass production of semicondutors for converter stations can reduce the biggest cost of direct current transmission. For the reduction of heat, larger diameter cables are not substantially more expensive to bury and heavy towers are not needed. This site became more boring when comments were restricted registered logged in users, so I will not suggest that any engineer who did not know that sodium has been used in cables not do any posting to the site. People can check Potassium on Wikipedia and find out that all live creatures have always been radioactive. Iron is toxic, and mothers' iron pills have sickened many a child. ..HG..

sulleny

EP - what did Toppa say here to deserve your rancor?

All this is backwards technology. The idea of generating power and then having to transmit it great distances is primitive and will feed energy monopolies political power far more dangerous than electrical.

The simple elegant fact there is energy all around us at all times appears to be lost on these big energy engineers. And while these massive projects do make work for restless workers - big electrical arteries in big electrical grids are high security risks.

ai_vin

OK yes, we know HG is a crank but I just googled "sodium cables" and it seems that he's not totally off his rock.

Engineer-Poet

Damn, he got me for once. All his rambling had me convinced he was off his rocker.

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