Power-system level classification of voltagesource HVDC converter stations based upon DC fault handling capabilities

Abstract

To date, numerous concepts for converter station designs for use in voltage source converter (VSC)-based highvoltage direct current (HVDC) systems have been proposed. These differ not only in converter circuit topology, sub-module design, and control scheme but also in AC-or-DC switchgear and other auxiliary equipment. In the main, the existing literature categorises these converter stations according to just the converter circuit technologies and controls. However, for the development of network codes and to enable systematic network studies, a system-focused and technology-independent classification is needed. As such a classification does not yet exist, this study proposes a new framework, which categorises VSC station designs according to their capabilities during a DC-side fault and the method by which post-fault restoration may be achieved, given that these are the main differentiating factors from a system perspective. The classification comprises six converter station types and three time-intervals through which to fully characterise a design. Many well-known forms of converters are used as case studies, and simulation results are used to exemplify the classification framework. The outcome is a generic and technology-independent way of characterising converter station designs that is useful in wider power-system analysis but also for putting proposed converter stations into context.