Comparative analysis of fault detection and classification techniques for HVDC grids protection

Abstract

Dealing with high short-circuit currents with a fast rise rate in Voltage Source Converters (VSCs) still poses as a challenge for High Voltage Direct Current (HVDC) multiterminal system (MTDC) reliability. Several fault detection algorithms have been proposed for multiterminal VSC-HVDC grids, such as undervoltage, overcurrent and their respective time derivatives. This work investigates their performance in terms of speed, sensitivity and correctness concerning classification. Tests were conducted by simulating pole-to-pole and pole-to-ground faults in different locations and fault resistances in a four-terminal VSC-HVDC grid. The results confirmed that voltage-based algorithms performed better than current-based algorithms in most cases. Furthermore, a voltage ratio method is proposed to increase fault classification performance during low-resistance faults.