International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 09 Issue: 07 | July 2022 www.irjet.net p-ISSN: 2395-0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2732 SHORT CIRCUIT ANALYSIS OF ELECTRICAL DISTRIBUTION SYSTEM FOR INDUSTRY APPLICATION USING ETAP SOFTWARE Manu K S 1 , Dr. C Santhana Lakshmi 2 , Dr. S Purushotham 3 , Dr. V Shanmugasundaram 4 , Dr. R Satheesh 5 1 Manu K S: Student, Dept. of EEE, SCT, Salem, Tamil Nadu, India 2 Dr. C. Santhana Lakshmi (co-author): Assist Professor (Sr Gd) Dept. of EEE, SCT, Salem, Tamil Nadu, India 3 Dr. S. Purushotham (co-author): Assist Professor, Dept. of EEE, SCT, Salem, Tamil Nadu, India 4 Dr.V. Shanmugasundaram (co-author): Assist Professor, Dept. of EEE, SCT, Salem, Tamil Nadu, India 5 Dr. R Satheesh (co-author): Assist Professor, Dept. of EEE, SCT, Salem, Tamil Nadu, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - An in-depth analysis of short circuits in power distribution systems for industry is presented. A power system short circuit study is performed to ensure the completeness of the equipment fault classification and to provide specifications for newly installed equipment to withstand the degree of short circuit that exists at each point in the system. Electrical systems Short circuit analysis helps ensure that personnel and equipment are protected, by establishing proper tripping ratings of the switches (breakers and fuses). If the extent of the system failure exceeds the interrupting capacity of the fault clearing device, the consequences can be severe. It can seriously threaten human life and cause personal injury, major property damage, fire, and costly downtime. In addition, the short circuit current obtained from the short circuit study is used for the relay coordination study. Key Words: Short circuit, Analysis, Industrial distribution system, Electrical power system study, Industry. 1. INTRODUCTION A short circuit study is performed to determine the magnitude of the potential current flowing in the power system at different time intervals after the fault has occurred. The amplitude of the current flowing in the power system after a fault differs with time until they reach equilibrium. The behavior is due to the characteristics and dynamics of the system. During this time, a protection system is required to detect, interrupt and isolate these faults. The duty for the equipment depends on the magnitude of the current, which depends on the time since the onset of the fault. This is done for different fault types (three-phase, phase-to-phase, two-phase-earth and phase- to-earth) at different locations in the system. The information is used to select fuses, circuit breakers and switchgear sizes in addition to protective relay settings. Even the best designed electrical systems sometimes experience short circuits resulting in abnormally high currents. Overcurrent protective devices, such as circuit breakers and fuses, must safely isolate the fault from a provided location with less damage to the circuit and equipment as well as less interference. for plant working procedures. Other system devices like cables, busbars and disconnecting switches, must be able to withstand the maximum mechanical and thermal stress caused due to the maximum short-circuit current flowing through those devices. The amperage of the short-circuit current is usually estimated by calculation, and the equipment is selected using the results of the calculation. The current during a short circuit at any point in the system is limited by the impedance of the circuit and the source equipment or sources at the fault point. It is not directly related to the size of the load on the system. However, additions to the system to increase the ability to handle growing loads, such as a larger or larger transformer from a utility, without affecting the normal load in some locations. Existing places within the system can crucially increase the short-circuit current at these points. When an existing system is expanded or a new system is installed, the existing short-circuit current must be determined in order to apply the appropriate overcurrent protection devices. The calculated maximum short-circuit current is almost always required. In some cases, minimum holding values are also necessary to verify the sensitivity requirements of current sensitive protective devices. The scale and complexity of many modern industrial systems can make long-term short-circuit current calculations impractical. Calculators are often used for large short circuit studies. 1.1 Characteristics of Short-Circuit Currents Full calculation of the short circuit currents will give the currents as a function of time at the position of the short circuit from the beginning of the short-circuit until its termination, corresponding to the instantaneous value of the voltage at the beginning time of short-circuit currents.