Influence of Arc Current on Energy Balance due to High Current Arc in a Closed Chamber

Self Cite

From an environmental viewpoint, when carrying out internal arc tests on SF 6 -insulated power equipment, it is necessary to prevent SF 6 from being released into the atmosphere or to replace SF 6 with air in accordance with IEC standards. However, the pressure rise and the thermal effect of the hot gas exhausted during arcing when testing in air are still considerably different from those for testing in SF 6 . Thus, it is necessary to propose a specific procedure to replace SF 6 with air and to select appropriate parameters for the tests. Therefore, it is desirable to clarify the equivalent conditions causing these phenomena both experimentally and analytically. In this paper, we describe the effect of the charged gas pressure in a closed container on the pressure rise due to air and SF 6 arcing and the ratio of the arc energy to the energy contributing to the internal pressure rise (k p ) from an experimental viewpoint. Additionally, to research the energy balance resulting from SF 6 arcing in the container, the energy balance is discussed on the basis of chemical reactions, radiation, and the melting and vaporization of the electrodes. It is found that the maximum pressure rise increases for both gases upon increasing the gas pressure from 0.1 MPa to 0.4 MPa. Subsequently, good agreement with the energy balance was obtained under reasonable assumptions by taking account of the energy components related to the chemical reactions, radiation, and the melting and vaporization of the electrodes. The ratio of the radiation energy loss to the total consumption energy increased upon increasing the charged gas pressure. C⃝ 2016 Wiley Periodicals, Inc. Electr Eng Jpn, 195(3): 26-37, 2016; Published online in Wiley Online Library (wileyonlinelibrary.com).

Section: Resultsmentioning

confidence: 62%

Section: Energy Balance In Closed Container In Case Of Sf6 Arcmentioning

confidence: 92%

“…As can be seen from the diagram, the arc energy (

E_{arc}

) produced in a closed container is consumed not only in raising the pressure, but also in heat transfer to the electrodes (

E_{cond}

), electrode melting and evaporation (

E_{m}

E_{v}

), radiative loss (

E_{rad}

), and so on. Energy is generated by an oxidative reaction between the metal vapor emitted by the electrodes and the oxygen contained in the air (

E_{oxi}

) , and is generated or consumed by a fluoridation reaction between the metal vapor and SF 6 gas (

E_{flu}

), SF 6 gas decomposition (

E_{gas}

) , and so on. The energy of the chemical reactions between gases and metal vapor depend on whether arcing occurs in air or in SF 6 gas.…”

Section: Energy Balance In Closed Container In Case Of Sf6 Arcmentioning

confidence: 99%

“…We also consider four components of the total consumed energy

E_{cons}

(kJ), namely, the energy contributing to the pressure rise

E_{pre}

(kJ), the electrode melting energy

E_{m}

(kJ), the electrode vaporization energy

E_{v}

(kJ), and the radiative energy loss

E_{rad}

(kJ). The resulting energy balance is shown below; we ignore the energy

E_{cond}

of heat transfer to the electrodes :

E_{arc} + E_{flu} + E_{oxi} + E_{gas} = E_{pre} + E_{m} + E_{v} + E_{rad} .

Section: Energy Balance In Closed Container In Case Of Sf6 Arcmentioning

confidence: 99%

See 2 more Smart Citations

Pressure Rise due to SF₆ Arcing and Energy Balance in a Closed Container

Kotari

Tadokoro

Tanaka

et al. 2016

Self Cite

“…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

Self Cite

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