Flashover performance of ice-covered post insulators with booster sheds using experiments and partial arc modeling

According to operational experience of power systems, the outdoor insulation strength can be reduced due to the effect of rain. Till now, little work has been done to investigate the flashover performance of air gapped arresters under rain conditions. Therefore, in this paper, experiments were carried out and the AC flashover performance of 10 kV arresters with different air gap structures was studied. The experimental results show that, for the tested arresters, the flashover current mainly flows through the air gaps and zinc oxide varistors under rain conditions. It is also confirmed that the flashover voltages decrease with the increasing of rain intensity and conductivity. In the windward direction, the wind can distort the water streams between the air gaps and rise the flashover voltages. In the leeward direction, if the rod electrode is beyond the range of the plane electrode, the flashover voltage researches the smallest value when the wind speed is 4 m/s. Analysis and discussions have been done to explain the experimental results, and the research in this paper may provide reference to improve the flashover performance of air gapped arresters under rain conditions.

Section: 2effects Of Rain Intensitymentioning

confidence: 99%

AC Flashover Performance of 10 kV Rod-Plane Air-Gapped Arresters under Rain Conditions

Xie

et al. 2018

“…S.M. Ale-Emran proposed using a high-speed camera to observe the characteristics of the partial arc on the ice-covered post insulator with booster sheds, and simulated the electric field distribution of the insulator when a partial arc occurred based on the finite element method [16]. However, the simulation analysis was carried out in two-dimensional axisymmetric state, which is different from the three-dimensional electric field of insulators after the partial arc occurrence.…”

Section: Introductionmentioning

confidence: 99%

Influence of Partial Arc on Electric Field Distribution of Insulator Strings for Electrified Railway Catenary

Zhao

Zhang

et al. 2019

The occurrence of a partial arc can affect insulation properties of the insulator by different types of flashover. In order to investigate the influence of a partial arc on electric field distribution along the catenary insulator string, a three-dimensional model of the cap-pin insulator string with partial arc was established in this paper. The electric field distribution along the insulator string when the arc extended on the insulator surface and bridged sheds was investigated based on the electric field analysis using the finite element method. The results showed that the occurrence of a partial arc caused obvious distortion of the electric field, which was a two-dimensional axis symmetrical field before arcing to a three-dimensional field. In the case of arc extension, the sudden rise of field intensity was mostly at the rib and the shed edge, which had the local maximum field intensity. The rib and the shed edge played a certain hindrance role in the extension of the arc. The main reason for promoting the development of the arc can be attributed to thermal ionization. In the case of arc bridge sheds, the highest field intensity appeared at the edge of the last bridged shed. As the number of sheds arc-bridged increased, the maximum field intensity also increased. As the arc length increased, the electric field intensity of the arc head also increased, which resulted in an accelerated arc development. The main factor to promote the development of the arc can be attributed to electrical breakdown. The measures to hinder the rapid development of partial arcs were proposed.

“…It is proved that the variations of sheds configures can affect the number and length of the air gaps on the iced insulators, and the air gaps can impact the insulators' icing flashover performance [16]. Experimental studies were carried out, and the booster sheds were found to be an effective way to improve the icing flashover performance of composite insulators [17]. The booster sheds effects on the flashover performance of ice-covered post insulators have been studied using experimental and simulation methods [18].…”

Section: Introductionmentioning

confidence: 99%

Voltage Distribution and Flashover Performance of 220 kV Composite Insulators under Different Icing Conditions

Xie

Jiang

et al. 2018

Abstract:Composite insulators are widely used in modern power systems to provide electrical insulation and mechanical support for transmission lines and substations. However, the insulation strength will decrease greatly under the combined conditions of ice-covering and contamination, and icing flashovers may take place under these serious conditions. In this paper, AC flashover tests of different artificially ice-covered 220 kV composite insulators were carried out in a multi-function artificial climate chamber under energized ice accumulation conditions. The test results indicate that, with the increasing of ice thickness, the flashover voltages decrease and tend to saturation. The icing flashover voltages can be increased by adding booster sheds, but excessive booster sheds can lead to lower flashover voltages under heavy icing conditions. The voltage distributions of the iced insulators were measured using experimental methods. The results show that, the air gaps withstand most of the applied voltage. The zinc oxide (ZnO) resistors that are contained in the insulators can influence the voltage distributions of the iced insulators, but have little affect on the icing flashover voltages. The work done in this paper can provide reference for the design and type selection of outdoor composite insulators in cold climate regions.