hvdc transmission assessment

Since the rebirth of hvdc transmission in Europe in 1954, for long distance underwater application, there are more than 20 hvdc systems totalling about 15,000 MW capacity in either commercial operation or construction throughout the world. Performance of hvdc systems, in terms of availability and utilization, has been improving rapidly with the advent of solid-state valves. Applications of hvdc systems for power transmission over long distances using either overhead lines or underground/underwater cables, asynchronous links, enhancement of system stability and reduction of short circuit duty are foreseen for the future. Research efforts in compact dc terminals, higher ratings of converter valves, reliable controls, hvdc circuit breakers and environmental effects of hvdc transmission lines will enhance increased acceptance and improve operating performance of hvdc systems in existing ac networks. The evolution of hvdc systems is discussed, major factors responsible for the utilization of hvdc transmission technology throughout the world are identified and its future in the USA is forecast.