Novel Approach for Arcing Fault Detection for Medium Low Voltage Switch gear

Switchgear arcing faults have been a primary cause for concern for the manufacturing industry and safety personnel alike. The deregulation of the power industry being in full swing and ever-growing competitiveness in the distribution sector calls for the transition from preventive to predictive maintenance. Switchgear forms an integral part of the distribution system in any power system set-up. Keeping in mind the switchgear arcing faults, the transition mentioned above applies most of all to the switchgear industry. Apart from the fact that it is the primary cause of serious injuries to electrical workers worldwide, switchgear arcing faults directly affect the quality and continuity of electric power to the consumers. A great amount of technological advancement has taken place in the development of arc resistant/proof switchgear. However, most of these applications focus on minimizing the damage after the occurrence of the arcing fault. The problem associated with the compromise on the quality and continuity of electric power in such a scenario still awaits a technical as well as economically feasible solution. This paper describes the development of a novel approach for the detection of arcing faults in medium/low-voltage switchgear. The basic concept involves the application of differential protection for the detection of any arcing within the switchgear. The new approach differs from the traditional differential concept in the fact that it employs higher frequency harmonic components of the line current as the input for the differential scheme. Actual arc generating test-benches have been set up in the laboratory to represent both medium and low voltage levels. Hall-effect sensors in conjunction with data acquisition system are employed to record the line current data before, during and after the arcing phenomenon. The methodology is first put to test via simulation approach for medium voltage levels and then corroborated by actual hardware laboratory testing for low voltage levels. The plots provided from the data gathering and simulation process clearly underline the efficiency of this approach to detect switchgear arcing faults. Both magnitude and phase differential concepts seem to provide satisfactory results. Apart from the technical efficiency, the approach is financially feasible considering the fact that the differential protection is already being comprehensively employed worldwide.

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