Protection Scheme Design for Star Connected PMSG Based Wind Farm against Line Faults

Parallel topology for star connected wind farms integrated with utility grid via voltage source Inverter (VSI) is a favorable topology. Faults in wind farms can be either AC or DC in nature. AC faults do not affect much the voltage source converters (VSC) connected with wind farms but DC faults damage these converters badly. This paper analyses faults and proposes protection scheme against different DC faults for star connected wind farms. Secondly, protection for the DC line is designed in such a way that if a fault occurs at any of the DC lines connected with VSC, the only faulty line should be isolated and thus providing protection to the remaining system. Moreover, the control system is designed in such a way that in case of single-source isolation remaining system will supply power to the utility grid and VSC and generator remain protected by inclusion of damping resistors.