Circuit Model and Analysis of Molded Case Circuit Breaker Interruption Phenomenon

Abstract

There are complex physical phenomena for the interpretation of a molded case circuit breaker (MCCB) in a distribution system. Most of the studies of MCCB interruption phenomena were conducted with numerical analysis and experiments. This traditional approach may help improve the performance of the MCCB itself, but it is difficult to find connectivity with other systems. In this paper, the circuit model is proposed and the interruption phenomenon of MCCB is analyzed. The interruption of the MCCB is divided into three sections to deal with physical phenomena occurring in each area. A simplified model is proposed considering the characteristics of each section. Based on this model, the circuit model is proposed. To implement the features of each section, the calculation of physical phenomena is carried out, and this is expressed in the circuit model with resistance and zener diode. Comparing the results of the simulation with the experimental results is as follows. For 7-plates (basic state), the error rate is −5.6% in section II and 16.8% in section III. For 1-plate, the error rate is 36.5% in section II and −17.0% in section III. This case shows much difference from the simplified model in this paper, resulting in the largest error rate. The 7-plates and 5-plates cases, which are available in the general MCCB owing to the shortest distance from the arc, represent a relatively small error rate. Using the proposed circuit model, it is expected that the entire system, including the interruption phenomenon, can be interpreted as a single circuit model.

Assessment of Cable Length Limit for Effective Protection by Z-Source Circuit Breakers in DC Power Networks

“…When one CLL curve has been developed and tested, the CLL curves for other conditions can be derived based on the existing one. By performing numerical analysis on the data of the CLL assessments in Sections 3 and 4, it was found that a new CLL curve could be developed according to (7): CLL New = P base P New × CLL base (7) In (7), CLL base and P base are the existing CLL point and its related power delivery level, respectively, and CLL new and P new are the new CLL point and its related power delivery level, respectively. When the effective length of the ZCB is measured and calculated for the base condition, all the other effective length curves can be generated conveniently with (7).…”

“…The quenching of such an arc is the most significant concern since it increases the cost of maintenance and reduces the lifespan of the breaker [4][5][6]. A circuit model of a molded-case circuit breaker (MCCB) is proposed and the interruption phenomenon of the MCCB is analyzed in [7]. The dielectric recovery strength of a low-voltage MCCB is improved by changing the splitter plate [8].…”

Two-Level Excitation Current Driver to Reduce the Driving Power of an Electromagnetic Contactor

“…In the future, when the full DC power demand is achieved, many MCs are expected to be driven by DC power owing to the lack of sufficient alternating current (AC) power [4,5]. Moreover, in the existing AC networks, the use of DC-type MC is increasing to prevent the malfunction of the surrounding electronic devices owing to arcs generated when the MC is turned off [6,7]. For this reason, studies on the electromagnetic effect occurring in DC excitation-type electronic contactors are also being actively conducted [8,9].…”

Multiline Fault Current Limiter for DC Line Fault in Multi‐terminal DC Grids

“…The currently proposed DCCBs can be mainly divided into three types: the mechanical DCCB, the solid-state DCCB, and the hybrid DCCB [6][7][8][9]. Since the solid-state DCCB has extremely high power losses during normal operation, it is more appropriate to be adopted in the low-and medium-voltage dc systems [10].…”