Abstract
The flashover performance of insulators is the foundation of the calculation of precise lightning protection. The material and structure of an insulator affect its flashover performance but the research on the differences in the flashover performance of different insulators and the analysis of the reason for these differences have not been clear. In this paper, lightning impulse flashover tests of two types of insulators (composite and glass insulators) were carried out in the National Engineering Laboratory (Kunming) for Ultrahigh-voltage Engineering Technology. In these tests, the insulators were hung in a 110 kV double-circuit transmission tower and a standard lightning impulse (1.2/50 μs) was applied to the insulators. The discharge path and the 50% impulse flashover voltage of the insulators were recorded. At the same time, the electric fields in the vicinity of different insulators were calculated using the finite element method with COMSOL Multiphysics. The electric field distribution and the uneven coefficient were analyzed. Combined with the flashover test data and the electric field simulation, the relationship between the flashover performance (discharge path and 50% impulse flashover voltage) and the electric field (electric field distribution and uneven coefficient) is found. The simulation results are in accordance with the test data and the conclusions can provide useful references for the external insulation design of transmission lines and the optimization of insulators.
Highlights
The lightning impulse flashover performance of insulators is the basis for the external insulation design of transmission lines
The purpose of this paper is to study the lightning impulse flashover performance of the insulators with different materials and structures in clean and dry conditions and to analyze the reason for the differences in flashover performance by corresponding electric field simulation
Typical lightning impulse discharge processes of composite and glass insulators are shown in Figures 3 and 4 respectively
Summary
The lightning impulse flashover performance of insulators is the basis for the external insulation design of transmission lines. The discharge path and the 50% impulse flashover voltage (U50% ) are significant parts of the flashover performance. The electric field around an insulator can affect the discharge formations and influence its flashover performance. For this reason, the analysis of the electric field around insulators is important for the further study of different flashover performances and discharge mechanisms. Since the middle of the 19th century, numerous types of insulators have been used in power transmission lines, such as glass and composite insulators. In order to investigate the flashover performance of different insulators in different conditions, a large number of experiments have been
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