Study on the performance of open-circuit failure gas discharge tube under the context of DC short-circuit

Abstract

Protective devices are used at every single port of electrical equipment, such as gas discharge tube(GDT), metal oxide varistors(MOV), and transient voltage suppressors diodes(TVS). These devices are capable to absorb lightning, surge, static electricity and other burst waves by directly spanning across both ends of the circuit or grounding mode. When the protective devices overabsorb these burst waves, short-circuit failure will result. The short-circuit failure of protective devices is one of the potential hazards that would cause combustion. In order to avoid the fault combustion of GDT caused by short-circuit, an open-circuit failure gas discharge tube (OGDT) with the capacity of open-circuit failure is proposed by improving the existing GDT with a high and low temperature sealing solder. This paper focuses on exploring the structure and working mechanism of OGDT, with the open-circuit failure response arc extinguishing time of the OGDT measured by coupling the DC power supply with an 8/20 μs impact current generator. The impact of short-circuit current and DC voltage on OGDT response arc extinguishing time is analyzed by conducting experiments and the effect of OGDT is verified by adjusting the area of low temperature weld. The results show that with the rise of short-circuits current, the open-circuit response arc extinguishing time of OGDT first decreases and then increases. A larger area of the low-temperature welding solder leads to a shorter the response arc extinguishing time. Besides, the higher the applied DC voltage, the shorter the response arc extinguishing time. When the short-circuit current reaches 10 A, the optimal response arc extinguishing time is 300 ms. When the short-circuit current falls below 25 A, the response arc extinguishing time of OGDT can reach a lower level than 1000 ms. The OGDT open-circuit failure action screen is captured by a high-speed camera to verify its outcome. The high-speed camera captures the OGDT open-circuit failure and excision failure at 300 ms, which is consistent with the experimental waveform results. The research results provide practical guidance on the selection of OGDT.