Circuit breakers 500 kV degradation in substation reactors caused by inductive current

摘要

During the interruption of inductive currents, once the switch contacts start to move, and as the current approaches zero, there is an unstable interaction between the resulting arc inside the switch chambers and the equivalent capacitance between the terminals of the switch. This interaction results in a negative damped oscillation in the current that eventually produces the current chopping. A chopping current phenomenon is caused energy stored in the line reactors, in the form of an electric field, causing high transient overvoltage in the line reactors and high requirements of the Transient Recovery Voltage (TRV) on the associated switches. The analysis describes the failure engineering analysis and the maintenance experience in a real case study, which develops the methodology to obtain improvements inside the switch chambers, in an electrical substation for 500 kV overhead lines; besides a proposal for diagnosis and remaining life for this assets in the power industry.