Academic literature on the topic 'Sulphur Hexafluoride (SF6) Circuit Breaker'

Abstract A 126kV circuit breaker was found to have latent fault by SF6 decomposition product detection method. It was found that the sulfur hexafluoride gas decomposition products of the circuit breaker contained a large amount of CO gas, a certain amount of SO2 and H2S, and a small amount of HF gas. The characteristic components and their contents of the decomposition products were analyzed, it is preliminarily concluded that there is insulation material fault in the circuit breaker, and the potential fault is further confirmed by the disassembly inspection that the MoS2 lithium base grease is overcoated at the metal tie rod joint.

In recent years, the C4F7N mixed gas has attracted considerable attention for its outstanding insulation and arc-extinguishing capabilities, positioning it as a potential substitute for sulfur hexafluoride, SF6. However, there remains a limited understanding of the arc-extinguishing and insulation performance of C4F7N/CO2 mixed gas. In addition, there is limited research on high-current breaking in circuit breakers. Therefore, this study aims to investigate the arc characteristics and breaking behavior of 10%C4F7N/90%CO2 and 15%C4F7N/85%CO2 mixed gases using a magnetohydrodynamic model based on the 252kV air pressure circuit breaker. The dynamic characteristics of this mixed gas are compared with pure SF6 under short-circuit current breaking conditions, while analyzing different parameters of the C4F7N configuration. The results indicate that the mixed gas exhibits lower levels in terms of arc temperature, axial diffusion distance and pressure difference at the moment of arc initiation compared to pure SF6. Furthermore, increasing the inflating pressure can effectively enhance the breaking performance of the circuit breaker with 0.6 MPa, making it more suitable. Additionally, increasing the proportion of C4F7N in the mixed gases will cause the arc temperature to rise slightly at the initial arc and current crossing zero, but decrease at the peak current. The core pressure also rises significantly, with a greater pressure difference established in the compressor at moment of arc initiation. This study provides a reference for the design of an environmentally friendly circuit breaker and the selection of the mixed gas ratio.

Abstract. The development of technology in the current era is very rapid and has an impact on increasing electrical energy which is a major need for large industries and households. One of the electrical energy delivery equipment in the transmission system is a PMT or High Connection Breaker. This PMT is a mechanical equipment equipped with sulfur hexafluoride (SF6) gas arc extinguishing media. The process of extinguishing the arc occurs due to contact due to work from the movement that causes the contact to cause an arc. This decrease in SF6 gas pressure greatly affects reliability when operating, because the arc extinguishing process is not perfect. This is determined by the age of the equipment and the number of operating breakers. The results showed that SF6 gas which is in accordance with the standard normal pressure of 6.4 bar with an ambient temperature of 34°C can minimize the occurrence of equipment damage because it is able to approach arc pressure with SF6 gas velocity of 58 cm/s.kA, with a contact gap of 3,61224. cm, while the PMT cannot be operated at a pressure of 5.2 bar with an ambient temperature of 34°C because the speed of SF6 gas is 82 cm/s.kA with a contact gap of 5.10696. It is concluded that the higher the pressure affects the speed and distance when extinguishing the arc. several factors that affect the decrease in SF6 gas pressure using the FMEA method based on the highest value of the Risk Priority Number (RPN) of 810. Keywords: fire arc, Breakdown, Voltage breaker, SF6 . gas pressure

This study investigates the breakdown voltage characteristics in sulfur hexafluoride (SF6) circuit breakers, employing a novel approach that integrates both experimental investigations and finite element simulations. Utilizing a sphere-sphere electrode configuration, we meticulously measured the relationship between breakdown voltage and electrode gap distances ranging from 1 cm to 4.5 cm. Subsequent simulations, conducted using COMSOL Multiphysics, mirrored the experimental setup to validate the model’s accuracy through a comparison of the breakdown voltage-electrode gap distance curves. The simulation results not only aligned closely with the experimental data but also allowed the extraction of detailed electric field strength, electric potential contours, and electric current flow curves at the breakdown voltage for gap distances extending from 1 to 4.5 cm. Extending the analysis, the study explored the electric field and potential distribution at a constant voltage of 72.5 kV for gap distances between 1 to 10 cm, identifying the maximum electric field strength. A comprehensive comparison of five different electrode configurations (sphere-sphere, sphere-rod, sphere-plane, rod-plane, rod-rod) at 72.5 kV and a gap distance of 1.84 cm underscored the significant influence of electrode geometry on the breakdown process. Moreover, the research contrasts the breakdown voltage in SF6 with that in air, emphasizing SF6’s superior insulating properties. This investigation not only elucidates the intricate dynamics of electrical breakdown in SF6 circuit breakers but also contributes valuable insights into the optimal electrode configurations and the potential for alternative insulating gases, steering future advancements in high-voltage circuit breaker technology.