A Single-End Reactor Voltage Based Protection Scheme for Meshed VSC-interfaced HVDC Grids

The protection of high-voltage direct current (HVDC) grids is a crucial aspect in ensuring the reliable and efficient operation of modern electrical energy transmission systems. The high amplitude and rate of change of fault current as well as the presence of multiple paths for fault current contribution of voltage-sourced converters make the protection of HVDC grids with meshed configuration a challenging task. This paper develops a protection scheme for these grids that has three modules: (i) low-resistance fault detection module based on the amplitude of the voltage across the current limiting reactor (CLR) at the line terminal, (ii) high-resistance fault detection module based on quantifying the severity of the CLR voltage signal change, and (iii) fault classification module. No need for communication links increases the reliability and operating speed of the proposed scheme. Moreover, severity measurement based protection increases the sensitivity of fault detection. The ability to faulty line identification in the meshed configuration verifies the selectivity of the proposed scheme. In addition, its robustness is verified due to low susceptibility to measurement noise, DCCB operation, AC fault, various CLR sizes, and power reversal. Several pole-to-pole and pole-to-ground fault scenarios with various fault resistances at different fault locations are conducted to verify the reliable performance of the proposed HVDC protection scheme.