Underfrequency Load Shedding using Locally Estimated RoCoF of the Center of Inertia

The conventional Under Frequency Load Shedding (UFLS) scheme could result in unacceptably low frequency nadirs or overshedding in power systems with volatile inertia. This paper proposes a novel UFLS scheme for modern power systems whose inertia may vary in a wide range due to high penetration of renewable energy sources (RESs). The proposed...

High-Speed Distance Relaying of the Entire Length of Transmission Lines without Signaling

Short-circuit faults close to either end of a transmission line, are normally cleared instantaneously by the distance relay at that end and after hundreds of milliseconds, i.e., in Zone 2 operating time, by the relay at the opposite end of the line. This sequential tripping can be accelerated on condition that a reliable communication link is...