Detection and Classification of Faults in MTDC Networks

DC line faults raise significant concerns in multiterminal high voltage direct current (MTDC) networks. The fault current ascends rapidly with a sharp peak, but isolating the entire faulty part is a non-sustainable solution for this matter. Therefore, rapid detection and classification of faults with high accuracy is indispensable. In this paper, a protection scheme is presented to protect MTDC networks based on voltage source converter (VSC) for interconnection of renewable energy sources, which incorporates main protection and post fault analysis. The main protection uses the Successive Data Window Technique (SDWT) as a fault detector, later on verifying it with the harmonics of the system voltage so as to prevent maloperation of the breakers, while the post fault analysis makes use of the voltage drop to classify the nature of fault, in addition to providing a backup in case the prior fails. The simulations results validate the protection scheme, which precisely identifies the fault and classifies its nature effectively. The performance of the proposed scheme is evaluated in PSCAD for MTDC networks. Matlab also verifies the results making this scheme a promising one.