Circuit breakers can fail to interrupt fault current when the power system has transient recovery voltage (TRV) characteristics that exceed the rating of the circuit breaker. There were two incidents of failures of outdoor switchgear at a power plant substation. The cause of the failure for these breakers was investigated in order to determine if transient recovery voltage is a contributing fac...

Breaking waves generated by wave shoaling in coastal areas have a close relationship with various physical phenomena regions. Therefore, it is crucial to accurately predict breaker indexes such as breaking height and depth when designing structures. Many studies on been carried out, many experimental data documented. Representative provide empirical formulas for the prediction of index, mainly ...

The violent event of a short-circuit leads to short-term exposure of circuit breaker components to extremely high current, causing thermal degradation, vaporization and deformation of some components and the deposition of surface contaminants. After short-circuit, the leakage current carried by the breaker, when voltage is applied, increases dramatically but must remain below a certain threshol...

A two-dimensional compressible magnetohydrodynamic (MHD) computational model has been developed to study the effect of gassing material on air arc behavior in low voltage circuit breaker. The properties of arc plasma and the electric, magnetic and radiative phenomena have been taken into account in the model. Based on the model, steady state solutions have been performed to study the effect of ...

In a biased weak (a, b) polyform achievement game, the maker and the breaker alternately mark a, b previously unmarked cells on an infinite board, respectively. The maker’s goal is to mark a set of cells congruent to a polyform. The breaker tries to prevent the maker from achieving this goal. A winning maker strategy for the (a, b) game can be built from winning strategies for games involving f...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. The pressure distribution directly affects its performance. So an investigation on the flow characteristics inside the annular foam breaker is important to optimize its structure. In this paper, the computational fluid dynamics (CFD) code, FLUENT, is employed to simulate the flow ...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. Its effectiveness in destroying drilling foam has been test in wellbore flow simulation loop experimental stand. Experimental results showed that the operating pressure of the annular foam breaker should be larger than 0.6MPa and the stabilizers concentration of the foam drilling ...

In a (1 : b) Maker-Breaker game, one of the central questions is to find the maximal value of b that allows Maker to win the game (that is, the critical bias b∗). Erdős conjectured that the critical bias for many Maker-Breaker games played on the edge set of Kn is the same as if both players claim edges randomly. Indeed, in many Maker-Breaker games, “Erdős Paradigm” turned out to be true. There...

Longshore transport experiments were conducted in a large-scale physical model to evaluate predictions of the CERC formula with measured longshore sediment transport rates. It was found that the CERC formula produced reasonable estimates if the coefficient K was calibrated and applied to waves with similar breaker type. The calibrated K values are much smaller than values that are commonly used...

Nowaday, the traditional circuit breaker is which action slow, poor reliability, can not meet large grid interconnection and flexible AC transmission requirements. To address those shortcomings of traditional circuit breaker, an idear is put forward that traditional mechanical circuit breaker combinates of power electronic switch-IGCT to build a new type of hybrid circuit breaker device (Hybrid...