Multi-Terminal DC System line Protection Requirement and High Speed Protection Solutions

For long distance and high power transmission, high-voltage direct current (HVDC) transmission is a preferred solution due to its technical and economic advantages. A multi-terminal HVDC (MTDC) transmission system either based on voltage source converters (VSC) or line-commutated converters (LCC) has also been introduced recently. With the development of fast and high breaking capability HVDC circuit breakers, the collapse of the MTDC network voltage resulting from DC line faults can be prevented and the disturbances to the connected AC grid can be minimized by using related protection systems. Therefore, it is required to have a fast and selective DC line fault detection and location methods using initial transient fault signatures.