In TechTopics No. 53, the characteristics of SF6 (sulfur hexafluoride) gas that make it advantageous for use in mediumand high-voltage electrical equipment were discussed. This issue of the TechTopics series will discuss this issue further by comparing the features of conventional, medium-voltage loadinterrupter switches operating in air with those operating in an SF6 gas environment.
The table on the next page shows some of the major characteristics of medium-voltage load-interrupter switches that influence the application or the space required. Of course, the table data for air switches is generic, and the specific data for a particular vendor of air switches can vary significantly. The air switch dimensions shown are for the most common (15 kV 600 A) switch, and the dimensions for a 27 kV switch are significantly greater. Even though typical data is used for the air switch, the table is considered valid for an overall understanding.
From the data in the table, these observations can be made:
- Endurance: The switching endurance of the type SIMOSEC SF6 switch is significantly higher than that of an air switch that merely meets the ANSI C37.22 endurance requirements.
- Environmental: The switching performance does not deteriorate in adverse environments since the type SIMOSEC SF6 switch is isolated from the atmosphere.
- Size: The type SIMOSEC SF6 switch (without operator) is over 90 percent smaller than the basic air switch, allowing for a great reduction in space for the overall type SIMOSEC switchgear installation.
- Maintenance: Maintenance required for the switch itself is essentially eliminated.
This comparison illustrates the superiority of the type SIMOSEC SF6 load-interrupter switch in comparison to traditional loadinterrupter air switches.
Should you have any questions about this issue of TechTopics or any of our products, solutions, or services, please contact your local Siemens sales representative for more information.
