• 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.

• 대한기계학회논문집B
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• 제30권2호
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• pp.95-100
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• 2006

Electrostatic precipitators(EPs) have low pressure drop and high dust collection efficiency and are widely used for industrial dust collectors. The current-voltage characteristics, which are important to maintain high dust collection efficiency, depend on several factor: discharge electrode shape, gas flow property, dust loading etc. In this study, experiments are performed to investigate the current-voltage characteristics of the corona discharge of various electrode geometries and an empirical model is proposed to predict current-voltage characteristics of the corona discharge. The corona onset voltage correction coefficient$(\alpha)$ and the geometry correction coefficient$(k_g)$ are used to the conventional equation for wire-plate type discharge electrode. The corona onset voltages are -6.3kV and almost constant when the numbers of discharge pins are varied from 3 to 9. The length of discharge pins has very sensitive effects on the corona onset voltage. They are increased from -6.3 to -7.8kV when the discharge pin length are 8.5 and 4.5mm, respectively. The empirical model shows good agreement with experimental results and can predict the effects of discharge pin length and number.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1174-1180
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• 2015

We investigate in this paper the radiated electromagnetic waves together with the discharge characteristics of Trichel pulse of negative DC corona discharge in air in pin-to-plate and wire-to-plate configurations. The feature of the current pulse and the frequency spectrum of the electromagnetic radiations were measured under various pressures and gas gaps. The results show that the repetition frequency and the amplitude of Trichel pulse current depend on the discharge conditions, but the rising time of the pulse relates only to the radius of needle or wire and keeps constant even if the other conditions (including the discharge current, the gas gap and the gas pressure) change. There exists the characterized spectrum of electromagnetic waves from negative corona discharge in Trichel pulse regime. These characterized radiations do not change their frequency at a given cathode geometry even if the averaged current, the gas gap or the air pressure changes, but the amplitude of radiations changes accordingly. The characterized electromagnetic radiations from Trichel pulse corona relate to the formation or the rising edge of current pulse. It confirms that the characterized radiations from Trichel pulse supply information of discharge system and provide a potential method for detecting charged targets.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.60-62
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• 1988

In this study, the characteristic of charging current which flows into the polymer by applying the corona discharge carriers on the polymer surface was measured, so as to investigate the phenomenon of charge injection and movement if injected charge on polymer. Also. the characteristics of discharge current which flows by shorting both sides of corona charged polymers were measured. Experimental results are as follows; The amount of charges injected by corona discharge vary according to the state of surface and the type of carriers, and then the charging current varies according to the properties of injected carriers.

• 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.

• 전기학회논문지P
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• 제57권2호
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• pp.146-152
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• 2008

The frequency of lightning is increased due to improbable weather condition and global wanning. This phenomenon increases economical damage as well as human damage. Advanced countries like europe and north america have applied the facility standard of lightning by accumulating a store of quantitative data about lightning research. Lightning facility is composed of the lightning accepting part for induction lightning, ground connected electrode which conducts lightning current. The lightning accepting part is composed of normal rod, horizontal conductor, ESE lightning rod. Moreover, lightning accepting part is taken to use by the method of protection. This paper suggests HEC(Hybrid ESE-Conductor) method which mixes horizontal conductor and ESE lightning rod. This is also discovered by experiment that the starting point of corona discharge current is low, so it is efficient for lightning protection comparing with other methods. Moreover, distribution of electric field is analyzed qualitatively by finite element method. It also results in the relation of the starting point of corona discharge current. Corona discharge current makes minute current about some ${\mu}A$ between the electrodes by the strength of electric field. Also it occurs insulation destruction of gas, and it is developed to the shape of streamer by increase of the strength of electric field. We can find that the initial occurrence of streamer and contact probability of lightning can have advantage after researching the starting point of corona discharge current and discharge current of lightning striking point. This research demonstrates that the suggested HEC method is economically competitive as a lightning protection facility, and it takes a capably perfect role.

• 설비공학논문집
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• 제16권4호
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• pp.318-323
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• 2004

When a strong electric field is applied between a sharply curved electrode and a blunt surface, the corona may result in a gas movement in the electrode gap which is directed toward the blunt surface. That is called the corona wind. It enhances heat and mass transfer between the surface and the surrounding gas. Moreover such enhancement causes no noise or vibration, which can be applied in complex, isolated geometries, and allows simple control of surface temperatures. This paper examines the relationship between the corona wind and the relative humidity. The facility consists of high voltage power supply thin tungsten wire, plate electrode, multimeter, microammeter and flow meter. Gas velocity is a linear function of voltage, relative humidity and is proportional to the square root of the current. The maximum velocities for the positive and negative corona discharge are 1.9 m/s (2.74 CMM/m), 1.5 m/s(2.15 CMM/m), respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권5호
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• pp.245-249
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• 2006

Corona characteristics of conductors are dependent on the electric field conditions in the immediate vicinity of the conductors. In case of DC transmission line, particularly, the space charge plays an important role in the electric field distribution. Therefore, DC corona cage simulation is necessary for long-term test in the same conditions. This paper presents the results of designing and constructing hardwares such as DC power supply, measurement system and DAS to carry out the simulation. The corona cage longitudinally is divided into five equal length sections and three inner sections of those are isolated from the ground of outer cage. The measurement items are radio noise, corona current, television noise, audible noise and meteorological conditions. In the next step, various simulations about the type and configuration of two or three candidate conductors will be conducted. And then finally an environmentally-friendly conductor for HVDC overhead transmission line will be decided.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.520-527
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• 2006

The electrical discharge and operational characteristics of needle and wire-cylinder corona charger based on current measurements for positive and negative coronas were evaluated and compared. A semi-empirical method was used to determine the ion concentrations in the charging zone and at the outlet of both chargers. Results from experimental investigation revealed that magnitudes of the charging current from the wire-cylinder charger were approximately 3.5 and 2 times smaller than those from the needle charger for the positive and negative coronas, respectively. The ion number concentrations at the outlet for positive corona of both chargers were higher than fur negative corona at the same voltage. Flow and electric fields in the charging zone of both chargers were also analyzed via numerical computation. Strong electric field strength zone was identified and led to high charging and particle deposition. Effect of particle deposition on the evolution of discharge current was presented. It was shown that ions loss inside the wire-cylinder charger was higher than the needle charger The particle deposited on the corona electrodes and on the grounded cylinder caused a great reduction in charging efficiency of both chargers.