アークによる密閉容器内圧力上昇に及ぼす電極材質の影響

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SUMMARYThis paper describes experimental and analytic studies on pressure rise and propagation phenomena due to high current arcs in a container with opened pipes. The shape of the experimental container was chosen taking into account underground common ducts. First, arcs were ignited in the container with varying diameter D and length L of the opened pipes and at arc currents of 4 kA to 12.5 kA and an arc duration of 0.1 s. Based on measured waveforms, the maximum pressure rise P and the pressure oscillation frequency P were obtained. It was found that there is a tendency for P to increase with decreasing D and increasing L, and that D has a much greater impact on P . In addition, the tendencies of P with changing D and L can be approximately explained by Helmholtz resonance. Second, a CFD model for the container with opened pipe was developed based on the experimental results, and simulations were performed. The simulation results were found to correspond to the experimental pressure rise. C⃝ 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 190(3): 30-36, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com).

Section: Introductionmentioning

confidence: 99%

Pressure Rise and Propagation Phenomena Due to Fault Arc in Container with Opened Pipe

Miyagi

Tanaka

Iwata

et al. 2014

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“…Although phenomena of internal pressure rise due to arc have been examined in various points of view [9–19], there are still no sufficient understandings or evaluation methods, and theoretical prediction of such phenomena remains extremely difficult. Consequently, we have searched for fundamental understandings via experiments with closed chambers of relatively simple shape, and based on the experimental results, we have developed methods for appropriate evaluation [20–24].…”

Section: Introductionmentioning

confidence: 99%

Dependence of internal pressure rise due to arc on current waveform and ignition position

Tanaka¹,

Miyagi²,

Iwata³

et al. 2012

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This paper describes an experimental study concerning the pressure rise due to high current arcs in a closed chamber. In this study, the arcs were ignited in certain chambers of varying size under the same conditions, namely, an arc current of 12.5 kA and an arc duration of 0.1 s. Moreover, the pressure rises in the chambers were measured while varying the current waveform, namely, the frequency of the AC power source and the DC component of the current, and the ignition position. Based on each measured waveform, not only the maximum value ∆P max but also the middle value ∆P mid , which was the midpoint of the amplitude around the time point of ∆P max , were extracted. As a result of the evaluation using both ∆P max and ∆P mid , it was shown that ∆P max / ∆P mid varied with both the current waveform and the ignition position, whereas ∆P mid was independent of them. Through FFT analysis of both the pressure rise and the arc power waveforms, it was verified that this experimental result was related to the resonance effect between the pressure rise and the arc power oscillations.

Proposal on modeling of pressure rise and propagation due to short‐circuit fault arc on a CVT cable installed in a protective pipe

Tadokoro

Ohtaka

Amakawa

2012

In underground distribution systems, a CVT (cross‐linked polyethylene insulated PVC sheathed triplex) cable is installed in a protective pipe. When a fault arc occurs on the CVT cable, the pressure instantly increases due to the high temperature of the arc, then propagates in the pipe. The pressure rise and its propagation may seriously damage the pipe and connected power equipment. There are many different sizes of pipes and cables depending on the installation situation, and fault arcs occur under various conditions. Therefore, the simulation technique is effective for examining such pressure rise and propagation in addition to short‐circuit tests. The objective of this paper is to present a CFD (computational fluid dynamics) modeling that can be used to evaluate the characteristics of the pressure rise and propagation due to a fault arc in the protective pipe. The pressure‐rise waveforms obtained by CFD analysis were found to be similar to those from short‐circuit test results. In addition, the dependence of the maximum pressure rise on the size of the CVT cable and on the arc current was simulated well. Therefore, CFD modeling is sufficient for study of the pressure rise and its propagation in a protective pipe. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 9‐18, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22291