UHVDC Transmission

A new transformer developed for the world’s first ultra high-voltage DC transmission systems (UHVDC) has successfully completed final testing. It is the first transformer for the new 800 kilovolts (kV) HVDC in China. Today’s HVDC transmission systems normally operate at a standard transmission voltage of 500 kilovolts. HVDC systems can transmit power over much greater distances and at considerably reduced loss than is possible with AC systems.

To achieve this 60-percent increase in peak voltage capacity, Siemens had to develop a range of entirely new technical solutions for the new 800-kilovolt HVDC transmission system. One of several major challenges facing the company’s development engineers in Nuremberg was a lack of any defined standards for this scale of system. Due to the very high operating voltage, for example, they had to design exceptionally effective insulation systems. Therefore, in order to achieve the needed insulating clearances in air, the two valve bushings through which the current flows from inside the transformer to the converters are 14 meters in length. To construct the 800 kV transformers, a new, specially air-conditioned production hall had to be built to prevent the insulation from absorbing moisture from the atmosphere during final assembly. Similarly, the test facility in the Nuremberg factory had to be adapted to accommodate the tremendous increase in voltage when carrying out final acceptance testing on the new transformer.(CAN U ABLE TO FIND OUT TWO PERSONS ARE STANDING NEAR TO IT...IMAGINE ITS SIZE)