| Abstract |
At present, the high-voltage direct-current (HVDC) electric power systems are more simple in operation or planning compared to AC systems and they become more competitive, more practical and more economical. The development ot HVDC converter systems using high voltage thyristors has also opened new possibilities for better optimisation of the system. This article presents some aspects on the design and development possibilities of HVDC systems and their future requirements for converter valves. Future applications are discussed with special emphasis on economic aspects, design of converter control, availability and reliability of the system with its other auxiliary equipment. The article concludes with a presentation of thyristor valve protection and testing procedures for both normal operation and fault conditions. |
