System and method for measuring instantaneous gas density for conversion from long-air-gap streamer discharge to leader discharge

Abstract

The invention relates to a system and method for measuring instantaneous gas density for conversion from long-air-gap streamer discharge to leader discharge. The system includes an LED chip, a bean expanding lens, a main lens, a convergent lens, a knife edge, a telephoto lens and an ICCD camera. A discharge zone is generated between the main lens and the convergent lens. A coupling lens focuses self-luminescence generated by discharging and transmits the self-luminescence into a photomultiplier. The photomultiplier converts optical intensity time domain signals of the discharge self-luminescence into a voltage waveform and inputs the voltage waveform into a TTL pulse formation circuit. An output end of the TTL pulse formation circuit is connected to an input end of a digital delay generator, and the output end of the digital delay generator is connected to a pulse drive power supply and the ICCD camera separately. The system and the method can achieve accurate inversion measurement ofan ns-stage instantaneous gas density distribution rule in a process of conversion from long-air-gap streamer discharge to leader discharge, and have advantages of high system reliability and a high capturing efficiency.

Description

technical field [0001] The invention relates to a system and method for measuring instantaneous gas density of long-gap streamer pilot discharge conversion, specifically a measurement system and method for instantaneous gas density in the dark zone of long-gap streamer-pilot discharge conversion, which belongs to high-voltage test technology The field of discharge plasma diagnostics. Background technique [0002] Long air gap discharge usually refers to the air discharge phenomenon with a length of 1 m to tens of m. Long air gap discharge is the basis of research on external insulation configuration and lightning protection of power system. Streamer discharge and leader discharge are two discharge electron processes that dominate long air gap breakdown. Streamer discharge is composed of many discharge branches with low equivalent conductivity, and the free electrons generated provide energy for the formation of the leader. The pilot discharge is a thermal ionization phenom...

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Problems solved by technology

[0023] Aiming at the above-mentioned problems that the long air gap discharge current injection-leader conversion process lasts for a short time, there is randomness in the moment of occurrence, the change of gas density is small, and it is difficult to measure accurately, the purpose of the present invention is to provide a long gap streamer pilot discharge conversion Instantaneous gas density measurement system and method

The invention can realize the accurate inversion measurement of ns-level instantaneous gas density distribution law in the streamer-leader discharge conversion process, has the advantages of high system reliability and capture efficiency, and solves the problem of low temporal and spatial resolution of existing M-Z interference and schlieren imaging methods 、 Difficult to adapt to the problem of gas density measurement in streamer-leader discharge transformation stochastic process

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