Efficient computation model of du/dt for travelling wave protections on HVDC transmission lines

du/dt is one of the most important features for voltage travelling waves on occurrence of a dc-line fault, and it is often used to construct an action criterion for Travelling Wave Protection on HVDC transmission lines. In order to alleviate the sharp contradiction between the accuracy and efficiency in obtaining the trend of du / dt by traditional simulations, this paper proposed a global-sensitivity-based efficient computation method. The global-sensitivity concept is proposed and derived first, then the detailed implementation scheme, which is based on Vector Fitting Method (VF) and Thiele-type continued fraction interpolation technique, is presented. Finally, numerical examples show that the high computation accuracy can be achieved, at the same time, the proposed method has a huge advantage in saving CPU time to obtain the trend of du/dt over traditional simulations.