Online Assessment of Contact Erosion in High Voltage Gas Circuit Breakers Based on Different Physical Quantities

Abstract

In this paper, an effort has been made to evaluate the online condition of arc contacts as a vital component of interruption chamber in high voltage puffer type SF6 circuit breakers. The relationship between eroded mass caused by shortcircuit current interruption and different thermal stress indices such as transferred electrical charge, current squared, and arc energy is investigated, by performing many experiments with different current amplitudes and arcing times. It is demonstrated that none of the known indices can solely determine mass erosion caused by the current interruption. Therefore, the equations including two of defined parameters are proposed to evaluate mass erosion. The method using arc energy and transferred electrical charge owns the highest accuracy in evaluating mass loss. However, considering the complexity of arc voltage measurements, a second method using current and arcing time can be also utilized. In addition, the development of erosion during the lifetime of arc contacts is studied. It is shown that arc roots tend to form on new uneroded areas of the contacts during current interruption, resulting in different erosion rates between the first few and subsequent interruptions due to change of morphology of the contacts after the first few switching operations.

Condition Monitoring of High Voltage Circuit Breakers: Past to Future

“…In this effort, the arc energy is calculated based on the recorded arc current using current transformer, and the arc voltage through the proposed online measurement system. Other investigations have been performed to inclusively reveal the relationship between the eroded-mass caused by shortcircuit current interruption and different thermal stress indices such as transferred electrical charge, current squared, and arc energy in [45]. The mass loss is presented as a function of electrical parameters such as transferred electric charge, arc energy, or integral of current squared.…”

“…In addition, consideration of the voltage needs special measurement tool to record the arc voltage in a precise manner while withstanding the high voltage transients. Furthermore, comprehensive experimental tests are required to extend the energy basedindex for all CBs [45].…”

Line Protection Operate Time: How Fast Shall It Be?

“…Therefore, the current interruption occurs again at the third zero-crossing, with identical FCT of 36.6 ms. It is not only that the faster operate time has not lead to a shorter FCT, but instead, the circuit breaker was exposed to much higher stresses since the arcing time was significantly longer (17.1 ms instead of 7.6 ms) causing higher wear of the CB arcing contacts which further contributes to the reduction of its service lifetime [7,16]. For this reason, the relay operate time is not relevant by itself; only the fault clearing time has a meaningful effect on the rest of the power system.…”

Study on the Influence of Reignition on Electrical Life Distribution of Low-Voltage Circuit Breakers

“…The electrical life of a low-voltage circuit breaker mainly depends on arc erosion during interruption. When arc erosion reaches a certain extent, the electric contact state and arc extinguishing reliability are affected [4][5][6]. The switch apparatus electrical life calculation methods include the accumulative arc energy method, relative electric wear method, and weighting breaking current accumulation method [7,8].…”