Discussion of simplified methods for short-circuit current calculation in HVDC networks

HVDC technology is being used increasingly in many areas, so it is essential to derive international standards for determining short-circuit currents in HVDC grids. As there are currently no regulations, this report makes proposals for a procedure. Various short-circuit types are described so that it is possible to calculate the maximum short-circuit current for the design of devices on the DC side. It is proposed to determine the steady-state short-circuit current using a simplified calculation method based on the converter’s U/I characteristic. The converters are modelled as voltage-dependent current sources resulting in an implicit equation that needs to be solved. In contrast, the other electrical parameters, including the short-circuit peak current, are strongly influenced by the time constants of the components and the capacitive discharge of the lines, capacitors, and filters. In these cases, a detailed transient calculation using a calculation program is more appropriate.