V-T Characteristics of Epoxy Mold Insulation for Sustained AC Voltage

The grounded back electrode can reduce the breakdown voltage. Inserting an insulation barrier is an effective way to increase breakdown voltage. The objective of this paper is to investigate the impact of barrier on AC breakdown with back electrode. The breakdown voltage is acquired from the experiments. The electric field distribution at breakdown is also obtained via software simulation. The experiments and analysis for both 'with' and 'without' back electrode are performed. From the results, the barrier can effectively increase breakdown voltage, especially for the case with back electrode. Without back electrode, there is only one breakdown trajectory path. The breakdown trajectory is very similar for all breakdown cases without back electrode. However, with back electrode, there are three breakdown trajectory patterns in total. The behaviors of breakdown voltage and electric field vary between different patterns. The analysis indicates that electric field distribution controls breakdown characteristics. The partial discharge (PD) streamers and residual charge induced by the electric field is the key to explain all the phenomena.

Section: Without Back Electrodementioning

confidence: 54%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of insulation barrier on AC flashover voltage with and without grounded back electrode in air

Liu

Karady

2015

“…It has also been found that a highly divergent electric field can result in the generation of corona and streamer. Such partial discharge, therefore, can be hazardous to the operation of the power equipment [16]. However, current studies have yet to propose a detailed electric field distribution under the influence of back electrode or establish the relationship between the breakdown characteristics and the electric field distribution.…”

Section: Introductionmentioning

confidence: 99%

Influence of grounded back electrode on AC creepage breakdown

Liu

Karady

Alamer

et al. 2013

Solid insulation using back electrodes has been adopted in various types of electrical equipment. This paper investigates the impact of back electrode on solid insulation AC creepage discharge characteristics. Breakdown voltages at different gap distances are obtained via experiments, and electric field distribution is calculated using computer software. We compare the results between 'with' and 'without' use of back electrodes, and investigate the internal relationship between breakdown properties and electric field distribution. It is observed that back electrodes result in concentration of the electric field near the high voltage electrode. A larger gap distance results in an increase in the maximum tangential electric field strength. When tangential electric field strength exceeds a certain critical value, partial discharge streamers are generated. Such streamers help to lower the breakdown voltage and make the maximum electric field strength less than expected value.Index Terms -Back electrode, creepage breakdown, electric field, partial discharge streamer, solid insulation.

Design of solid/gas composite insulation system with embedded electrode

Yamashita

Furusato

Asari

et al. 2019

Solid insulated switchgear (SIS) has been developed as a substitution for sulfur hexafluoride gas insulated switchgears in the medium voltage class. Its main circuit including a vacuum interrupter is coated with epoxy resin. Ａn embedded electrode was employed in order to enhance the surface insulation performance for further miniaturization and higher stress design. In the previous studies, the surface insulation performance was examined by using a model electrode system which modified the electrode system of the moving part of SIS and the estimation method of the surface breakdown voltage was proposed. In addition, the simulation of the surface breakdown characteristics of a model electrode system was conducted and a design method was proposed. In the present study, the insulation performance of the solid part was taken into account and the insulation design was conducted using the proposed design method. The "equivalent insulation distance" was introduced and the partial discharge inception field strength was also taken into account. The insulation design was done for 22, 33 and 77 kV systems and the values of the design parameters were provided. In addition, it was found that two different types of the design concepts were available.