Effect Of The Power Frequency On Impulse Flashover Performance Of Polluted Glass Insulators

Damage causing by lightning has a larger impact on the safety and stable operation of thepower system. With the development of the economic and the improvement of the voltage levels,lightning trip in polluted conditions has become one of the main reasons on transmission lines. Ithas an important role in guiding the lightning protection of transmission lines in polluted conditionsfor knowing well about the law of development on lightning impulse flashover under frequencyoperation of transmission lines. Therefore, it is necessary to analysis of the law of the developmentof polluted insulators being struck by lightning flashover on actual case. It can provide guidanceand basis for the configuration of the insulation level on transmission lines and for thedetermination of the protection on lightning level. Besides, it can reduce lightning trip accidents andimprove the security and stability due to pollution.Most of the researches about the effect on voltage impulse flashover performance under powerfrequency affect most of the discharge between gas gap, and not so many about polluted insulators.Besides，most of the existing researches only from the point of view of the U50%compared to reflectthe role of different factors, and there are few concerned about the development process offlashover, nor do consider the effect of the phase angle on impulse flashover performance.Therefore, this paper attempts to establish a new test platform about impulse flashover performanceon polluted insulator to analog the flashover of the polluted insulators being struck by lightning ofthe frequency voltage on operation, and then has an analysis of the effect on the impulse flashoverprocess of the Polluted Insulators on power frequency.This article firstly has a research on the way of the performance of the impulse flashover aboutthe contaminated insulators, designs a circuit which makes the power frequency and the impulsesuperimposed, and develops a device which makes the phase angle of power frequency and theimpulse synchronously, obtains the voltage waveform and achieves its observation synchronously.The circuit can equally analog the contaminated insulators suffered the lightning shielding indifferent phases. Then the article tests on the impulse flashover performance in the three cases ofpolluted insulators without processing frequency voltage, pre-processing frequency voltage andfrequency voltage superimposed, and have an observation of the discharge process on pollutedInsulators. Through comparative and analysis, we obtain the effects of the potential for the powerfrequency、the pre-discharge effect of power frequency and the drying effect of leakage currentunder power frequency on the impulse flashover investigated in the development process of two polluted insulators. Combining the effect of the AC amplitude on impulse flashover performance onpolluted insulators, the article summarizes the calculation method of two contaminated insulatorswith the power frequency superimposed impulse voltage under certain conditions, and then gives aformula of power frequency superimposed impulse voltage, which considers the impact factors ofthe contamination on surface of the insulators and the frequency voltage.