ARC FLASH ENERGY CALCULATION METHOD FOR ARC FLASH DETECTION AND CUTOFF

摘要

PURPOSE: A method for calculating arc flash energy for sensing and blocking arc flash is provided to easily and accurately calculate arc flash energy variable according to a variable and then warn and prevent disasters according to arc flash energy and arch energy distance, thereby safely protecting an electric element and a user from arc flash. CONSTITUTION: A method for calculating arc flash energy for sensing and blocking arc flash comprises the following steps. A set value including at least one among a panel type, a grounding, a three-phase short circuit current, a working distance, a conductor gap, a system voltage, and an equipment type is input in a computing unit in order to sense arc flash (S30). The computing unit calculates arc fault current by using the set value (S40). A protective relay or a circuit breaker that are connected to a conductor or a power element calculates the time required for operating to remove the arching (S50). The computing unit calculates arc accident energy by using the fault current and the set value (S60). The computing unit calculates the protection range by using the set value, the fault current, and the arc accident energy (S70). The set value, which includes at least one among a panel type, a grounding, a three-phase short circuit current, a working distance, a conductor gap, a system voltage, and an equipment type of the power circuit including the conductor or the power element, is input in the computing unit. The calculating the protection range further includes the following steps: calculating arc accident energy for each distance by using the set value, the fault current, and the arc accident energy by the computing unit; and calculating the protection boundary distance by the set value, the fault current, the arc accident energy, and the arc accident energy for each distance. In a case where the system voltage is above 15 KV and below 15 KV, the arc accident energy or the protection range is calculated by using different calculating expressions. [Reference numerals] (AA) Start; (BB) End; (S10) Document survey; (S20) Determine an operation mode of a power system; (S30) Setting input; (S40) Calculate arc fault current; (S50) Calculate arc duration time; (S60) Calculate arc accident energy; (S70) Calculate a protection range