Improperly protected short-circuit currents can injure or kill maintenance personnel. These currents can damage or deteriorate equipment. The building/facility may not be properly protected against short-circuit currents. All fault types can be simulated. Carelab’s short-circuit study provides a detailed report identifying breaker ratings, breaker fault duties, discussions, and recommendations for any deficiencies found Risks Associated With Short Circuit Currents Short-circuit calculations are required for the application and coordination of protective relays and the rating of equipment. The OCPD will also provide automatic interruption of overload currents. It provides this protection by automatically interrupting the large value of current flow, so the device should be rated to interrupt and stop the flow of fault current without damage to the overcurrent protection device. This will set the pattern to be used in other cases.Ī device that interrupts short circuit current, is a device connected into an electric circuit to provide protection against excessive damage when a short circuit occurs. In all cases, knowledge of the three phase bolted fault value is wanted and needs to be singled out for independent treatment. The three phase bolted short circuit currents are the basic reference quantities in a system study. These concepts will be stated and utilized in a step-by step development.
The application of three or four fundamental concepts of circuit analysis will derive the basic nature of short circuit currents. Fortunately, short circuit currents are relatively easy to calculate. Short circuit currents impose the most serious general hazard to power distribution system components and are the prime concerns in developing and applying protection systems. Knowledge of the computational methods of power system analysis is essential to engineers responsible for planning, design, operation, and troubleshooting of distribution systems. Basically, it is a low-resistance path of energy that skips part of a circuit and causes the bypassed part of the circuit to stop working. The reliability and safety of electric power distribution systems depend on accurate and thorough knowledge of short-circuit fault currents that can be present, and on the ability of protective devices to satisfactorily interrupt these currents. It can be in the form of heat or in the form of magnetic force. It is a specific kind of current that introduces a large amount of energy into a power system. Short-Circuit Currents are currents that introduce large amounts of destructive energy in the forms of heat and magnetic force into a power system. A short circuit is sometimes called a fault. The American National Standards Institute (ANSI) publishes both the standards for equipment and the application guides, which describes the calculation methods. Since the interrupting ratings are based by the standards, the methods used in conducting a short circuit analysis must conform to the procedures which the standard making organizations specify for this purpose. A Short circuit analysis is used to determine the magnitude of short circuit current, the system is capable of producing, and compares that magnitude with the interrupting rating of the overcurrent protective devices (OCPD).