by Mathcad Staff
Power system protection
About this worksheet:
- Calculates the fault current magnitude seen by the terminal breakers for any fault location
- Discusses power transmission and distribution, fault currents, fault voltage, ground fault protective devices, current transformers, and Thevenin’s impedance
- Iine impedance, current, and fault voltage is calculated between two buses
This worksheet shows you how to compute bus faults on power systems. Most faults in power systems occur at points on the line some distance away from the substation bus. These are called mid-line faults. This worksheet calculates the fault current magnitude seen by the terminal breakers for any fault location. This worksheet implements the method specified in Han's paper, "Generalized Method of Analysis of Simultaneous Faults in Electric Power Systems."
The line impedance (for each postive, negative, and zero sequences) between the two buses are calculated. The current can be calculated from the line impedances. As all these measurements are functions of the distance along the line, the bus fault voltage can be calculated at any point on the line. This method finds the minimum and maximum fault current values for any line segment in a system.
This worksheet provides you with examples for how to solve using PTC Mathcad software and shows how the total fault current magnitude of both three phase and single line to ground faults decrease as the fault location moves toward the center of a line segment, and proves how bus fault voltages on a bus increase as the location of the fault moves away from the bus of interest.
This PTC Mathcad worksheet provides you with step-by step notation, images, graphs, equations, formulas, and solutions to aid you in solving.
Download and explore this worksheet yourself! You can download a free lifetime copy of PTC Mathcad Express and get 30 days of full functionality.
