3.3.2 The Impact of Impurity Gases on the Breakdown Potential

    Seen from the foregoing discussion,α values and the breakdown voltage Vs valueare related to the nature of the gas (type and pressure),and are mainly determinedby the electron collision process with certain gas particles. If an electron in acollision has ......查看详细>>

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3.3.3 The Impact of Electrodes on Breakdown Voltage

    Electrode materials,especially the state of the electrode surface,have a greatinfluence on the process of emitting electrons from the cathode surface relying onradiation and positive ion bombardment. Thus the impact of the electrode on gasbreakdown potent......查看详细>>

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3.3.4 The Impact of Electric Field Distribution on Breakdown Voltage

    Electrode structure and polarity determine the electric field distribution in theelectrode gap before breakdown. The electric field distribution plays a decisiverole in the value and distribution of Townsend coefficients α and γ,limiting thetrajectories o......查看详细>>

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3.3.5 The Impact of External Ionization Source on Breakdown Potential

    An external ionization source can accelerate the formation of charged particles andreduce the breakdown potential of a gas. For example,heating the cathode artificially to generate thermal electron emission can replace the action of the γ emissionprocess;......查看详细>>

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3.4.1 The Steady-State Townsend Experiment(SST)

    In 1900,J.S. Townsend first proposed the use of the first ionization coefficient α todescribe the gas discharge,and proposed a method to measure the parameter α,namely the steady-state Townsend method (SST). Later,it was discovered that thedischarge chara......查看详细>>

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3.4.2 Pulse Townsend Method(PT)

    As mentioned before,the SST method can easily measure α,η parameters of a gas,applying a stable continuous light irradiated on the cathode to release electrons,forming a stable current I in the gap. According to the relationship between I andthe distance ......查看详细>>

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References

    [1] Zhancheng Wu,Xijun Zhang,Youzhi Hu (2012) Gas discharge. National Defence IndustryPress,Beijing[2] Xueji Xu,Dingchang Zhu(1996) Gas discharge physics. Fudan University Press,Shanghai[3] Dengming Xiao (1994) Research on discharge characteristics of the......查看详细>>

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4.1.1 Basic Properties of Spark Discharge

    4.1.1.1 Characteristics of Spark DischargeSpark discharge is different from the glow discharge and arc discharge. Thechannels of spark discharge exhibit discontinuity and the plasma in the crosssection of the discharge gap is not uniform. Its electrical s......查看详细>>

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4.1.2 Streamer Discharge

    4.1.2.1 Limitation of Townsend Discharge TheoryIn low pressure,Townsend discharge theory can be a good method to describe gasbreakdown and to illustrate Paschen’s law. But when near atmospheric pressure(Pd>70Pa·m),the theoretical discharge time-lag and......查看详细>>

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4.2.1 Experimental Study on the Long Gap Discharge in Air

    With the increase of the power system voltage level,long gaps occur more often inengineering (in non-uniform electric fields),for example,the insulation of highvoltage transmission lines,and insulation between high voltage equipment andwalls or ceiling. L......查看详细>>

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