• 한국자동차공학회논문집
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• 제10권6호
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• pp.65-71
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• 2002

Characteristics of corona discharge of the different types of the plasma reactors which are cone-hole and cone-plate is investigated experimentally. The discharge starts at lower voltage for the cathode corona than the anode corona and spark occurs at higher voltage for the cathode corona. And the cathode corona makes more stable discharge than the anode corona. The effect of the base gas in corona discharge for different O$_2$/N$_2$ concentrations is related with the gas molecular weight. The discharge for the smaller molecular weight gas occurs easier than for the high molecular weight gas. The discharge current decreases with the increase of oxygen concentration and it increases more sharply for anode corona than for cathode corona as discharge voltage increases after corona onset voltage. NO-NO$_2$ conversion increases with the energy density of corona discharge and the addition of O$_2$ in a base N$_2$ gas.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2089-2097
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• 2014

Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.

• 전기학회논문지
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• 제59권10호
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• pp.1862-1868
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• 2010

A corona motor, as one of a powerful cooling means of microelectronic devices, has been employed because of its very simple structure of no coils and no brushes. In this paper, the effect of polarity of applied voltage and the number of blade corona electrodes on the fundamental properties of rotation of the motor was investigated. The I-V and rotation characteristics of the blade corona electrode were significantly different from the different polarities of applied voltages and the blade corona electrode numbers, due to the different space charge effect resulted by the different migration mobility of the positive and negative ions generated near the blade corona electrode tip of the rotor of the motor. The rotation speed of the motor was influenced significantly by the polarity of corona discharge, the number of blades, and mass of rotor. At the same corona current, an effective rotation can be obtained with the positive corona caused by the lower ion mobility. On the other hand, the higher rotation speed can be obtained with the negative corona resulted from its higher corona current. The highest rotation speed and energy efficiency can be obtained with the rotor having 4 blades.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.74-81
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• 2015

In the measurement of atmospheric static electric field, it is important to know characteristics of corona discharges caused at the tip of test electrode. This paper presents the fundamental data of DC corona discharges that occurred at the tip of a needle-shaped electrode placed in the homogeneous background electric field which simulates the atmospheric static field under thundercloud. The major characteristics of interest for this purpose are the polarity effect of corona discharges and the magnitudes and time intervals of corona current pulses. The experimental set-up consists of the plate-to-plate configuration with a needle-shaped protrusion, DC power supply, and voltage and current measuring devices. As a result of experiments, the polarity dependence of corona pulses is significantly pronounced. The time intervals between successive corona pulses in the negative polarity is much longer than those in the positive polarity. The time intervals for both polarities is drastically decreased as the applied electric field is increased. Also the magnitudes of the positive corona pulses are slightly changed with an increase in applied electric field, but those of the negative corona pulses are linearly increased with increasing the applied electric fields.

• 전기학회논문지
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• 제59권12호
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• pp.2256-2261
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• 2010

A corona discharge system with needle point or wire type corona electrode has been well used as an ionic wind blower. The corona discharge system with a needle point electrode produces ions at lower applied voltage effectively. However, the corona discharge on the needle point electrode transits to the arc discharge at lower voltage, and it is hard to obtain the elevated electric field in the discharge airgap for enhancing the ion migration velocity due to the weak Coulomb force. A cylindrical corona electrode with sharp round tip is reported as one of effective corona electrode, because of its higher breakdown voltage than that of the needle electrode. A basic study, for the effectiveness of cylindrical electrode shape on the ionic wind generation, has been investigated to obtain an maximum wind velocity, which however is the final goal for the real field application of this kind ionic wind blower. In this paper, a parametric study for maximizing the ionic wind velocity utilizing the cylindrical corona electrode and a maximum ion wind velocity of 4.1 m/s were obtained, which is about 1.8 times higher than that of 2.3m/s obtained with the needle corona electrode from the velocity profile.

• 전기학회논문지
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• 제56권3호
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• pp.583-587
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• 2007

Corona discharge and ozone generation characteristics of a slit dielectric barrier discharge type wire-plate plasma reactor with a third electrode have been investigated. When a third electrode is installed on a slit of the slit barrier, where an intense corona discharge occurs, it is found that a significantly increased ozone output could be obtained. This, however, indicates that the third electrode can activate the corona discharges both of the discharge wire and the slit of the slit barrier in the plasma reactor. As a result, a thin stainless wire, used as the third electrode has a strong effect to influence the corona discharge of the slit and corona wire, especially to the negative corona discharge. Higher amounts of the output ozone and ozone yield, about 1.27 and 1.29 times for the negative corona discharge, can be obtained with the third electrode, which reveals the effectiveness of the third electrode.

• 대한전기학회논문지
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• 제32권5호
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• pp.157-163
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• 1983

Positive and negative coronas in point-to-plane short gap have been investigated with the variations of point radius and gap length. Mainly the onset potentials and current pulses under various conditions were measured with a 70 MHz C.R.O. and a precise-controllable D.C. power supply. In the case of negative corona, the Trichel pulse corona, glow corona and spark regions were distinguished apparently and the critical gap lengths between them were also found clearly. In the case of positive corona, there are streamer corona, spark regions and the critical gap length between them, too. The current pulse forms of Trichel pulse corona of negative and streamer pulse corona of positive are similar in rising time, peak-to-peak time and pulse width. The glow corona current shows D.C. component in form.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.51-56
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• 2001

본 논문에서는 침대평판 전극구조를 구성하여 침전극에 직류 정 ·부 고전압을 인가한 경우 전계와 자계가 직각방향으로 형성되도록 하고 자계가 코로나 방전현상에 미치는 영향을 측정하고 분석하였다. 정의 고전압을 인가한 경우 자계인가에 의해 방전코로나 영역이 확장되고 이때 흐르는 코로나전류가 감소하였고, 절연파괴전압은 증가되었다. 그러나 부의 고전압을 인가한 경우는 방전코로나 영역이 오히려 축소되고 흐르는 전류가 증가되었으며 절연파괴전압은 감소되었다. 이는 전자계가 동시에 존재하는 영역에서 코로나방전에 의해 생성된 전하들의 로렌쯔력에 의한 싸이크로트론 운동 때문인 것으로 생각된다.

• 한국통신학회논문지
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• 제4권1호
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• pp.32-37
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• 1979

신설된 345KV 송전선에 의해 야기되는 corona 잡음은 송전선 직하 10m 지점에서 주파수 1MHz시 相間의 간섭을 무시하면 최대 강우시 72dB, 젖은 도체는 63dB이고, 3상 전체의 corona noise 합성시는 제일 level이 큰 相이 지배적이다. 측정 결과 직각 거리 특성은 이론치와 잘 일치하고 기후 특성으로는 강우, 강설시 corona level이 제일 높았고 비온 전후로 수 시간이 경과해야 안정한 상태와 같아진다. 주파수 특성은 측정치와 보정식이 비교적 잘 일치한다. 측정된 corona 잡음으로 수신장해 정도를 나타내기 위해서는 통계적인 방법의 S/N 비 정량화가 필요하다. ITU, IEEE 위원회, 일본 NHK 등은 장시간에 걸친 시험 평가로 각각 품질등급에 따라 평가기준을 정의하고 있는데 우리나라에서도 수신품질에 대한 평가기준을 확립할 필요가 있다.

• 전기학회논문지
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• 제58권10호
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• pp.2005-2010
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• 2009

Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.