Effect of the humidity in the ionic mobility in reduced air-density

Calva, P.A.

doi:10.1109/ceidp.1998.732947

Cited by 12 publications

(11 citation statements)

References 12 publications

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“…Humidity has a significant effect on the corona inception voltage of and corona loss of conductors, however, no consistent opinion is obtained about the influence rule at present [4,5]. Furthermore, DC corona current decreases with the rise of humidity [6], which becomes more obvious under low air pressure [7].…”

Section: Influence Of Pressure and Humidity On The Amplitude -Phase Dmentioning

confidence: 91%

Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse

Meng

Hui

Mei

et al. 2013

2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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Corona problem is one of the important problems in the design and operation of the transmission lines. The corona discharge of high voltage transmission lines, results in power loss, radio interference and audible noise, which become more serious at the high altitudes. Besides, it has a great influence on the safe and robust operation of high voltage apparatus. A study carried out in the chamber made of perspex, was that AC corona characteristics varied with air pressure and humidity through the rod plane electrodes. The experiments showed that the inception voltage of AC corona was reduced with air pressure decreasing or humidity increasing. Meanwhile, the amplitude -phase distribution of AC corona pulse was displayed under different air pressure and humidity. Under low humidity (RH=25% or 55%), the streamer pulses only appear in the rise edge of positive half cycle, and the number of streamer pulses is few. The negative streamer pulses occur around the peak value of the negative half cycle. The streamer pulses appear in the rise and fall edge of positive half cycle at the same time with high humidity (RH=85%), and the number of streamer pulses increases obviously. When the humidity is higher (RH=95%), the streamer pulses appear only in the fall edge of positive half cycle. Furthermore, the negative streamer pulses around the peak of the negative half cycle also disappear.

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Section: Influence Of Pressure and Humidity On The Amplitude -Phase Dmentioning

confidence: 91%

Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse

Meng

Hui

Mei

et al. 2013

2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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“…Figure 8 shows the relation between U inc and H a under various air pressure conditions. When H a ranges from 5 to 15 g/m 3 , U inc increases slowly with the increase of humidity. However, when H a is high and ranges from 15 to 17.3 g/m 3 , U inc decreases obviously with the increase of H a , which is because of the fact that condensation occurs on conductor surface and distorts the electric field distribution around the conductor.…”

Section: Relation Between Corona Inception Voltage and Air Pressurementioning

confidence: 92%

“…When H a ranges from 5 to 15 g/m 3 , U inc increases slowly with the increase of humidity. However, when H a is high and ranges from 15 to 17.3 g/m 3 , U inc decreases obviously with the increase of H a , which is because of the fact that condensation occurs on conductor surface and distorts the electric field distribution around the conductor. The calculated results from the model, which consider and does not consider the effect of condensation, are compared with the measured results, as is shown in Figure 8.…”

Section: Relation Between Corona Inception Voltage and Air Pressurementioning

confidence: 92%

“…The wave-front time increases with the growth of air pressure and humidity. For example, when humidity is 5.5 g/m 3 and air pressure is 98.7, 78.7, and 58.7 kPa, the corresponding wave-front time is 50, 30, and 20 ns. When air pressure is 98.7 kPa and humidity is 5.5, 11.9, and 17.3 g/m 3 , the corresponding wave-front time is 50, 60, and 90 ns.…”

Section: Relation Between I Ave and Air Humiditymentioning

confidence: 99%

“…The continuous corona pulses refer to stable pulses or periodical pulses (several times per minute under DC). Figure 2 shows the waveforms of discharge pluses with the variation of U app when p = 58.7 kPa and H a = 17.3 g/m 3 . The pulse amplitude increases first and then decreases with the rise of U app .…”

Section: Determination Of Corona Inception Voltage and Glow Dischargementioning

confidence: 99%

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Influence of air pressure and humidity on positive direct current corona discharge performances of the conductor in a corona cage

Shu

Jiang

et al. 2013

Int. Trans. Electr. Energ. Syst.

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SUMMARYWith the implementation of West-to-East Power Transmission Project in China, transmission lines will inevitably pass through high altitude regions with complex atmospheric conditions. The effects of such atmospheric parameters as pressure and humidity on the corona discharge performances of conductors are complicated. Especially as to the effect of air humidity on corona inception voltage, researchers have not reached an agreement. Therefore, by adjusting air pressure and air humidity in a corona cage, the positive direct current corona discharge performances of a smooth steel tube are tested. Results indicate that corona inception voltage increases significantly with the increase of air pressure, and the calculated results by discharge model are in accordance with measured results. Yet, with the increase of absolute humidity, corona inception voltage increases slowly. Under high humidity condition, corona inception voltage decreases because of the condensation on conductor surface, which distorts the surface electric field. In view of the condensation, the calculating model is improved, whose calculated results are in line with measured results. Moreover, it is found that inception discharge is easier to turn into glow discharge under low pressure and low humidity condition. The average pulse amplitude decreases with the increase of humidity, but with the increase of pressure, it decreases first and then increases. The rising time of the discharge pulse presents increasing trend with the increase of both air pressure and air humidity. All the test results are analyzed from microscopic mechanism.

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Research on environmental factors of positive DC corona inception voltage of overhead transmission lines

Xu¹,

Wang²,

Zhao³

et al. 2012

2012 China International Conference on Electricity Distribution

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The corona discharge effect is one of important problems in the design and operation of transmission lines. The transmission lines pass by the high altitude region with low air pressure, which brings many special problems to the design and operation of the transmission lines. Temperature and humidity also have obvious effect on the corona characteristics of the transmission lines. Consequently, it is signiticant to study the impact of air pressure, temperature and humidity on the corona characteristics and discharge mechanism of transmission lines. A computation model is adopted for evaluating the corona inception voltage on conductors, which is established according to the gas discharge theory. The charge simulation method is introduced to the computation model to calculate the electric field intensity. Then the criterion of corona inception voltage which considers whether the number of positive ions in the secondary avalanches is greater or equal to that in the primary avalanche is used to calculate the corona inception voltage of conductors. The influence of air pressure, humidity and temperature on the corona inception voltage of conductors is analysed systematically. Corona inception voltage decreases as air pressure is lowered or temperature is raised. It is mainly due to the enlargement of ionization zone as a result of the increase of effective ionization coefficient. Simultaneity, corona inception voltage decreases with humidity increasing for strengthening of collisional ionization intensity.

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Effect of the humidity in the ionic mobility in reduced air-density

Cited by 12 publications

References 12 publications

Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse

Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse

Influence of air pressure and humidity on positive direct current corona discharge performances of the conductor in a corona cage

Research on environmental factors of positive DC corona inception voltage of overhead transmission lines

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Effect of the humidity in the ionic mobility in reduced air-density

Cited by 12 publications

References 12 publications

Influence of pressure and humidity on the amplitude &#x2014; Phase distribution of AC corona pulse

Influence of pressure and humidity on the amplitude &#x2014; Phase distribution of AC corona pulse

Influence of air pressure and humidity on positive direct current corona discharge performances of the conductor in a corona cage

Research on environmental factors of positive DC corona inception voltage of overhead transmission lines

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Product

Resources

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Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse

Influence of pressure and humidity on the amplitude — Phase distribution of AC corona pulse