Why does the vacuum trip continuously?
The formation and extinction of the arc in a vacuum
The vacuum arc is very different from the gas arc discharge phenomenon we learned before. The ionization of the gas is not the main factor in the generation of the arc. The vacuum arc discharge is formed in the metal vapor evaporated from the contact electrode. At the same time, the characteristics of the arc performance are different depending on the size of the breaking current. We generally divide it into small current vacuum arc and large current vacuum arc.
1. Small current vacuum arc
When the contact is broken in a vacuum, a cathode spot with a very concentrated current and energy is generated. A large amount of metal vapor evaporates from the cathode spot. The density of metal atoms and charged particles is very high, and the arc burns in it. At the same time, the metal vapor and charged particles in the arc column continue to diffuse outward, and the electrode also continuously evaporates new particles to supplement. When the current passes through zero, the energy of the arc decreases, the temperature of the electrode drops, the evaporation effect decreases, and the density of particles in the arc column decreases. Finally, the cathode spot disappears when it passes through zero, and the arc is extinguished.
Sometimes, the evaporation effect cannot maintain the diffusion speed of the arc column, the arc suddenly extinguishes, and the current is cut off.
2. High current vacuum arc
When the contact disconnects a large current, the energy of the arc increases, the anode also heats up seriously, and a strong concentrated arc column is formed. At the same time, the effect of the electromotive force is also obvious. Therefore, for a high current vacuum arc, the magnetic field distribution between the contacts has a decisive influence on the stability and arc extinguishing performance of the arc. If the current is too large and exceeds the limit breaking current, it will cause breaking failure. At this time, the contact heats up seriously, and the current still evaporates after zero, and the medium is difficult to recover and the current cannot be disconnected.
Vacuum degree decrease: This is one of the reasons for the tripping of the vacuum circuit breaker. The reduction in vacuum degree will lead to a weakening of the arc extinguishing ability and an increased possibility of the arc reigniting, affecting normal operation. The reasons may include problems with the arc extinguishing chamber material or manufacturing process, resulting in tiny leaks, or aging of the sealing structure after long-term operation.
The tripping of the vacuum circuit breaker is a manifestation of its protection function, but it may also occur frequently due to the above reasons, affecting the stable operation of the system. Regular maintenance, checking the vacuum level, adjusting mechanical properties, and ensuring the electrical control circuit is normal are key measures to prevent and solve the problem of vacuum circuit breaker tripping.
VTZ-12F generator output-specific vacuum circuit breaker by Shaanxi West Power Tongzhong Electrical Co., Ltd. is an indoor AC generator circuit breaker designed for 15kV three-phase AC systems operating at 50Hz. It is primarily used in the generator output circuits of small to medium hydroelectric power plants, thermal power plants, new energy power generation units, and industrial circuits with self-contained power supplies, such as those in the chemical and processing industries.
VTZ-12F generator output-specific vacuum circuit breaker has many features:
1.High current capacity, high breaking capability, advanced technical performance, and superior manufacturing quality.
2.The DC component of the rated short-circuit breaking current is ≥75%.
3.Adopts an integrated operating mechanism.
4.When installed individually, the rated current can reach up to 6300A with natural air cooling, and up to 8000A with forced air cooling.
5.Insulation utilizes an elliptical cross-section design to meet tensile and bending strength requirements, using high-strength insulating pull rods and support rods.
6.Grading rings are designed between insulators and supports to ensure uniform electric field distribution.
7.The circuit breaker uses a fixed installation method, and the main circuit meets air insulation distance requirements.
Should you have any requirements in these fields, please feel free to contact us as per following information:
Email: xdtz04@westpowerelectric.com
Website: https://www.xdtzelectrical.com/
Tel:+86 917 3661109
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