HVDC transformers in China: Solutions for energy efficiency
By 2020, China’s power demand is expected to reach double the current consumption of the US. Thus, as the world’s top energy consumer, China is massively investing into building and improving its power grid. The goal is maximum autonomy and better efficiency. HUBER+SUHNER offers a wide range of products and solutions for better power grid monitoring.
Besides the high energy demand, China also has to cope with an uneven distribution of power generation locations and power consumption spots. Most of the power used by cities and dynamic economic zones in the east is generated by hydro, whilst coal and wind is used in the North, West and South of the country. As a consequence, enhancement of the power grid to enable power transmission over long distances has become necessary. While facing such challenges, HVDC appeared to be a key technology for China - HVDC stands for High Voltage DC transmission. It enables the bulk transmission of electrical power using direct current. Thanks to HVDC, power is transferred with less loss over long distance. It also makes networking between “inhomogeneous” power grids easier and more efficient.
China: World leader in HVDC
Prior to 2020, 60% of the HVDC systems installed in the world will be in China. By necessity therefore, China has become the world leader in HVDC. While in the past the country was mainly relying on foreign expertise, today, state of the art R&D centers and national institutes are massively investing in the development of their own HVDC solutions. Several recent projects illustrate their success. One example is the Nan Ao project, which will enable offshore wind energy to directly feed the Guangdong province. Another one is the Dalian project. The city of Dalian, located in the Liaoning province in North China, is divided into two parts. The southern part has become a dynamic economic zone, requiring more power supply. Unfortunately, it is surrounded by the sea, so its geography does not allow either easy power transfer nor new power plants to be built. However, thanks to a submarine HVDC transmission link the south of Dalian is now fed with energy coming from the northern part of the city, without the addition of any extra power plant.
Various solutions from HUBER+SUHNER
The core of a HVDC system is the transformer. Its size, voltage rating and base technology may vary, but HVDC transformers always require advanced control and monitoring systems. These systems are necessary to ensure safety and security of the equipment, for example against surge currents, and to continuously monitor AC & DC voltage to optimize power output. These controlling and monitoring systems mainly use fiber optics as a cost efficient and reliable way to transmit signals over long distances. With Masterline, ready to plug, HUBER+SUHNER offers a perfect solution for this application. Masterline optical fibers are perfectly suited to withstand a harsh environment, such as continuous high electrical fields, temperature variations, UV radiations and outdoor conditions found in HVDC stations. Masterline systems are usually combined with other optical patch cords and fiber management solutions from HUBER+SUHNER used in indoor control units close to HVDC transformers. In addition to optical components, HVDC transformers also require coaxial cabling and electrical wiring. In various projects in China, RG58 coaxial cables and RADOX cables from HUBER+SUHNER have been used. RADOX cables, for instance, were selected due to their voltage rating, but also because of their very small diameter and high flexibility. Trials and tests run by customers showed that RADOX cables were easier to handle and bend when only small spaces were available.
With its three technologies - radio frequency, fiber optics and low frequency - HUBER+SUHNER is able to offer comprehensive connectivity solutions within HVDC systems, combining coaxial, optical and electrical cabling. HUBER+SUHNER products also help the customer to solve very specific technical challenges, such as connection reliability under the harsh conditions of high electrical fields or fast installation through ready-to-use plug-and-play cable systems. As energy consumption is rising worldwide, the HVDC market is very promising – not only in China. HUBER+SUHNER hopes to see this local application being duplicated in the rest of the world, where HVDC solutions are also used and developed.