Protection oriented observability in multi-terminal HVDC systems

Voltage source converter (VSC) based multi-terminal HVDC systems (MTHVDC) require rigid detection and fault clearing techniques capable of detecting commonly occurring faults. Furthermore, reduction of installation cost implies minimizing the expensive current and voltage sensors. In this paper, a new observability analysis algorithm is proposed to obtain the minimum number of sensors and their placement, required to control and protect MTHVDC grid. The proposed algorithm is incorporated with a developed wavelet - fuzzy logic based protection algorithm to identify fault types and location with minimum number of sensors. A new software tool-box is created and applied to test systems to verify the validity and importance of the proposed algorithm.