Robust non-communication line protection scheme using novel quantities

A robust non-communication scheme for transmission line protection is presented. The scheme facilitates the simultaneous detection of the remote breaker operation in order to adaptively accelerate zone 2 tripping of the local zone. A modal transform-based decision algorithm is proposed to efficiently detect symmetrical/unsymmetrical faults. Modal quantities as well as current phase angle variations are monitored during and post-fault, and translated into hypothetical communication flags. Therefore, the benefits of modern communication-based schemes can be approached without utilizing physical communication links. A simulation study is carried out to investigate the scheme performance. Test results corroborate the high performance of the proposed adaptive scheme for variable faults