Study on Impulse Breakdown Characteristics of Internal-Gap Lightning Protection Device Applied to 35 kV Distribution Line

Abstract

External environmental factors have no effect on the breakdown performance of the internal gap, leading to the anti-icing and anti-storm features of the internal-gap lightning protection device (ILPD). In this paper, a test platform is created to study the impulse discharge and arc erosion characteristics of the ILPD applied to a 35 kV distribution line. The 50% lightning impulse voltage and discharge stability of the ILPD are experimentally analysed. The results show that the ILPD has good discharge voltage repeatability under multiple impulses. Under a positive lightning impulse, the 50% breakdown voltage of the ILPD is 3.8-11.4% higher than that of the outer-gap lightning protection device (OLPD). A finite element simulation model is created for electric field analysis. The maximum electric field strength of the ILPD is 4.68% lower than that of the OLPD, leading to a higher lightning breakdown voltage. High-speed camera shooting shows that the discharge arc may lead to the erosion of the discharge tube, reducing its insulation performance. A large current impulse test platform is set up for arc energy analysis, which indicates that more than 90% of the energy is absorbed by the varistor during lightning stroke. The quality and leakage current of the discharge tube did not change significantly after testing. Given the current design of varistors, the per unit length energy of arc is less than 4.5 J/mm due to the numerical calculation, which is far less than the experimental arc energy (25.0 J/mm). Therefore, arc erosion will not cause the insulation performance of discharge tube to decrease when using the current varistor design.

New Technical Parameters and Operational Improvements of the Metal Oxide Varistors Manufacturing Process

“…The first varistors developed during the 1950s and 1960s had ZnO as their main component, along with a single additive, like, for example, TiO 2 , SiO 2 , SnO 2 . As we know, the main progress was made when it was introduced Bi 2 O 3 as an additive, which virtually introduced the double junction at the intergranular layer [18].…”

Case Study about the Energy Absorption Capacity of Metal Oxide Varistors with Thermal Coupling

“…Border areas are the two sides of the varistor as well as the border between resin and air insulation, as shown in Figure 2a and Figure 2b. For modeling the heat transfer in case of both configurations, we used FLUX 2D, which is a dedicated finite elements-based software, suitable for this kind of complex applications, having cylindrical symmetry [16]. Figure 2a presents the finite elements-based mesh for the standalone configuration and Figure 2b presents the model for the parallel configuration, with the thermal brass coupling.…”

Non-Contact Measurement and Polarity Discrimination-Based Identification Method for Direct Lightning Strokes

“…The simulation model is composed of five parts, namely, the lightning source, the tower, the insulator, the transmission line, and the corona model. According to the field-acquired lightning current data [8], 1.2/50 is a standard lighting voltage impulse (SLVI) as defined by the international electro technical commission (IEC) 60060-1. A surge waveform of 1.2/50 or 2.6/50 can be used to simulate the direct stroke.…”

“…Different protection methods should be used according to the type of the lightning stroke fault. These stroke faults should be identified to efficiently adopt targeted measures against lightning and improve lightning protection design [5][6][7][8][9][10].…”