Condition Monitoring And Device Development Of Zinc Oxide Arrester With Gap

Today's world,As limiting the level of over voltage,Zinc oxide arrester is the important protection facilities for the safe and stable operation of power system.Due to the poor working environment and long running time features,Zinc Oxide valve is aging on the role of working voltage,damping under the effect of the explosion.Not only cannot play a limited role,but also may bring hidden dangers to the power system.Therefore,it is very important to study the condition monitoring and evaluation method of zinc oxide arrester and discover the arrester defect.For the line with the gap zinc oxide arrester,the normal operation have no leakage current,the valve aging mainly due to lightning shock,the existing diagnostic method based on the leakage current can not be applied.therefore,The lightning surge and aging characteristics of zinc oxide arrester were studied by doing the tests,The lightning shocks of the various voltage levels of the zinc oxide arrester has a threshold of the number of times of the impact of the valve,when the number of lightning shocks is greater than the threshold,The surge capacity of the arrester,residual voltage and other will be change significantly,arrester will loss of protection performance;and The threshold decreases rapidly with the increase of the amplitude of the lightning impulse current.Through the cumulative arrester greater than 10kA lightning shock times can basically determine the state of the arrester body.The mechanism of the impact of aging is mainly heat aging.In this paper,the arrester heating process is similar to the adiabatic temperature rise.Based on the analysis of the heat dissipation characteristics of the body,the law of the temperature rise of the arrester after the large current shock is obtained.That is,there is a general aging stage and a thermal collapse stage in the degradation process of the arrester valve.The general aging stage,the valve is still a good flow capacity and heat capacity,when arrester suffer high current shock the body temperature is not obvious;When the valve is near the inflection point,the flow capacity and heat capacity of the valve are still within the limit,but the power consumption has increased obviously.The temperature rise of the arrester has been obvious under the impact of large current.If the thermal collapse phase is reached,the power consumption and temperature of the valve are ramp up after overvoltage shock,and the arrester will be unavoidably damaged.Therefore,zinc oxide arrester with the gap aging or damp,or near the heat collapse of the inflection point,arrester's surface temperature was significantly higher by the impact of high current,As a reference to determine the operational status of the reference has a good feasibility,On the basis of this,proposing the on-line monitoring scheme of arrester based on the number of lightning shock and temperature rise,and the corresponding system and device are developed to provide reference for the follow-up arrester on-line monitoring scheme.