A fast method is presented for obtaining a first estimate of the expected number of spurious trips due to voltage sags. The method is based on an expression for the so-called critical distance (the radius of the exposed area in which faults lead to equipment trips) in radial power systems. Extensions of the method for nonradial systems, and transfer of sags due to single-phase and phase-to-phase faults to lower voltages are also presented.
展开▼
