Applications of Vacuum Interrupters

Vacuum interrupters are primarily employed in th e medium voltage range(1. 5-38kV) switchgear. In recent years the researchers have been able to successfully implement 145kV vacuum circuit breaker is showing below. Switchgear employing vacuum interrupters can be employed in the following categories :

1. Circuit breakers.
2. Capacitance bank switching.
3. Auto-reclosers.
4. Contactors.
5. Load switching.
6. Inductive current switching.

Limitations to the Use of Vacuum Interrupter Technology

In the recent years, vacuum interrupter technology has become a major choice in power systems. This is because even though SF6 has better arc quenching capability, it is now being considered as an environmental threat as it is identified as one of the major global warming gases. Thus vacuum interrupter technology becomes an environmental friendly alternative. However, cost and technical requirements become driving factors in selecting vacuum technology over the SF6 and air switching counterparts. We can explain this as follows:

1. In low voltage applications, the air switching technology becomes more suitable owing to the lower cost of the air switching equipment.
2. While in high voltage applications the performance of SF6 becomes superior to vacuum technology.
3. The major difficulty faced by the vacuum technology is the physically large interrupters that are heavy and pose handling and maintenance as well as cost issues.
4. Also, the contact materials need to be optimized for use at high voltages.

Conclusion

The vacuum interrupter technology is an environment friendly substitute to the SF6 but its use is restricted to the medium voltages due to cost and technological limitations. Recent researches have been able to implement vacuum circuit breakers at high voltages but the growing demand of power requires improved technologies to be able to extensively implement the vacuum interrupter technology.