Introduction
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). 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. In the United States, the America National Standards Institute (ANSI) publishes both the standards for equipment and the application guides, which describes the calculation methods. 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.
Fortunately, short circuit currents are relatively easy to calculate. The application of three or four fundamental concepts of circuit analysis will derive the basic nature of short circuit currents. These concepts will be stated and utilized in a step-bystep development. The three phase bolted short circuit currents are the basic reference quantities in a system study. In all cases, knowledge of the three phase bolted fault value is wanted and needs to be singled out for independent treatment. This will set the pattern to be used in other cases.
A 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. 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. The OCPD will also provide automatic interruption of overload currents.
This spreadsheet calculates following:
This spreadsheet calculates following:
- Size of diesel generator synchronous panel
- Total fault current of diesel generator synchronous panel
- Total equivalent impedance of diesel generator synchronous panel
- Short circuit current of diesel generator synchronous panel
File Size: 31 Kb
You May Also Like These E-Books:-
No comments:
Post a Comment