Super large capacity converter transformer

Super large capacity converter transformer

Vol. 8 issue 1

Introduction

Driven by the growing prosperity of fast-growing developing economies, the demand for energy will continue to grow in the future. In order to cope with the challenge of climate change, clean energy is more preferred in the world. Therefore, with the continuous development of the social economy, the proportion of electric energy in terminal energy consumption and the demand for electric energy are increasing. According to the forecast of the International Energy Agency (IEA) [1], the share of electricity in terminal energy consumption may exceed that of oil by 2040, which is currently less than half of oil. Electricity demand will also increase by 70 %, with more than 50 % of the demand growth coming from China and India.

How to transport clean energy such as wind, water, and other clean energy to the economic development with strong demand is the current research focus of the researchers. Especially in China, a country with a vast territory and unbalanced regional development, the energy transmission distance may exceed 1000 km, so the power transmission with large capacity and long-distance has become a necessary choice. However, the transmission capacity of the existing AC power grid is reaching its limit, and the loss of energy in ultra-long-distance AC system is also uneconomical. The huge demand for energy consumption and optimal allocation of resources promotes the rapid development of long-distance, low loss UHVDC (ultra-high voltage direct current) transmission technology. The UHV converter transformer connects the AC power grid and converter valve hall, which is an important component of UHV AC / DC conversion. Converter transformer accounts for 43 % of the total investment of the converter station, which is the highest technical level, highest value, and most core equipment in ± 800 kV DC transmission project.

 

The development history

In the 19th century’s debate about AC and DC, the AC system won out. However, with the development of power electronics, HVDC transmission technology has become popular because of its high system stability and low line loss. In 1954, the world’s first commercial HVDC transmission project undertaken by ABB was put into operation in Sweden. In the 1970s, Siemens began to develop a high voltage converter transformer. Since then, ABB and Siemens have been industry leaders in the design and construction of converter transformers. They provided converter transformers for the first two ± 800 kV UHVDC transmission projects in the world (Xiangjiaba-Shanghai project and Yunnan-Guangdong project) and made a breakthrough in the ± 1100 kV UHV converter transformer.

 

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