Switchgear Sequence of Operations

[BlaineXD]

Hey All,
I'm hoping you can help me out with a random question about some switchgear (Main-Tie-Main) that I am doing some research on. It appears that there are two automatic sequences of operations available: one is an automatic re-transfer sequence, and the other a manual re-transfer sequence. The manual re-transfer operations state that the tie breaker doesn't close when one of the main's detects loss of power.
What is the point to a manual re-transfer sequence of operations? I am pretty new to switchgear, but not having the tie close means that half of my branch circuits are losing power, right? Is this configuration for testing purposes, or is there a genuine reason that I am missing? I'm almost inclined to believe this is a typo....
I hope my question makes sense.

Thanks for all the help,
--Nate

 

[zog]

Well you already lost power to half your sub anyways, the difference is the manual sequence allows you to have control over re-energizing, some equipment dosen't like losing power then getting it back right away without some operator action first.

 

[charlie b]

I was involved in a project for which the utility insisted on a manual transfer scheme. That was because the load was so high that they wanted to prepare their distribution system for the changeover of power from one substation to the other.

 

[zxfabb]

I guess what confuses the OP is "...The manual re-transfer operations state that the tie breaker doesn't close when one of the main's detects loss of power."

If you start to "re-transfer", it implies that the tie breaker is already closed and one main breaker is open? If so the above sentence doesn't make sense.