Load Interrupter Switch for Medium Voltage Generators 2

[hugop973]

I have 4 medium voltage generators (13.8KV) connected to a paralleling switchgear. The generator's manufacturer is recommending to use a load interrupter switch, SF6 type, rather than a simple safety disconnect switch on each generator. I know that the circuit breakers in the paralleling switchgear provides protection to the generators, i.e. excitacion loss, etc. What is the purpose of using this load interrupter? Thanks

 

[alehman]

Most air switches in medium voltage switchgear are designed for load interruption as well. They may be using SF6 interrupters to reduce physical size.

 

[hugop973]

I guess my question is, why the manufacturer is worried about protecting each generator with a load interrupter switch when it's known that the medium voltage circuit breakers in the paralleling switchgear provide that protection. Why not to use a simple safety disconnect switch normally closed, used for maintenance purposes only, and is cheaper compared to a load interrupter switch?. Thanks

 

[ScottyUK]

Could be as simple as the SF₆ interrupter is the standard design and they are trying to save the cost of engineering a custom product when their standard offering exceeds the requirement of the custom design.


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If we learn from our mistakes I'm getting a great education!

 

[alehman]

They should be able to omit it if you don't want it.

If this is a packaged genset, sometimes they have integrated electronic protection relays which might be wired to open the interrupter. If so, you would need to provide an alternative interrupter/breaker wired to their controller or other protection that meets their requirements (and yours).