Experimental Study on Splitter Plate for Improving the Dielectric Recovery Strength of Low-Voltage Circuit Breaker

Abstract

The low-voltage circuit breakers are widely used to protect loads in the distribution system. Interruption reliability of circuit breakers is important because they are a protective device close to the customer. In particular, the re-ignition phenomenon leads to over-current blocking failure due to the arc re-formed between electrodes despite the normal trip of the circuit breaker. In this paper, in order to improve the interruption performance against re-ignition, the dielectric recovery voltage measurement system of the circuit breaker is used and the experiment of changing the splitter plate is carried out. Two experiments are carried out by changing the splitter plate, especially changing the material of splitter plate and the number of lower plates of the splitter plate. In the case of changing the material of the splitter plate, the analysis is conducted according to the thermal conductance. In the case of changing the number of lower plates of the splitter plate, the number of plates and their spacing are variables. Analyzing the results of the dielectric recovery voltage experiment, in the initial period, copper plates have the best value that shows 102.1% improvement compared to normal and Al shows 59.8% improvement compared to normal. These increases are related to the thermal conductivity of the three electrode materials. In the case of changing the number of lower plates of the splitter plate, the 8-plates and 9-plates show 84.5% and 36.1% increases compared to normal, respectively, in the initial period. It can be seen that too many plates interfere with heat dissipation. Since this study studies performance improvement during the initial period, there is not much difference in the later period. This is consistent with the experimental results. In this study, an experimental basis is provided for the dielectric recovery strength from a low-voltage circuit breaker. It is expected that this will contribute to the research to improve the dielectric recovery capability of the circuit breaker.

Analysis of Short-Circuit and Dielectric Recovery Characteristics of Molded Case Circuit Breaker according to External Environment

“…In other words, when the external temperature increases from 25 • C to 45 • C, it can be seen that both short-circuit characteristics and dielectric recovery strength deteriorate at a similar rate. This shows a similar tendency to the case of the experiment conducted previously by changing the thermal conductivity of the splitter plate [14]. The second external environmental condition is disturbing magnetic fields.…”

“…The previous paper confirmed the effect of the material of the splitter plate inside the arc extinguishment chamber on the dielectric recovery characteristics of the breaker [14]. In this test result, it was analyzed how the thermal conductivity of the material affects the dielectric recovery voltage through one-way ANOVA (Analysis of Variance) analysis [15].…”

“…The results according to the thermal conductivity of the splitter plate performed in the The temperature-dependent change is significant compared to the previous study. The results according to the thermal conductivity of the splitter plate performed in the past are as follows [14]. The thermal conductivity of copper, aluminum, and steel are 320, 196, and 62, respectively, where the DRV result of the initial period is 196, 155, and 97.…”

Analysis of Characteristics of Low Voltage Circuit Breaker by External Magnetic Field

“…[15]. In our precious research, the dielectric recovery strength according to materials of the splitter plate was studied and it was confirmed that the thermal conductivity of the material had a dominant effect on initial dielectric recovery [16].…”

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

“…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]. An auxiliary solid-state switching device, along with a pre-charged commutation capacitor or a passive network, is used in a traditional solid-state DC breaker to force commutation in the primary solid-state switching device by reverse biasing [2].…”