CT Saturation and Lightning

[sobeys81]

Hi My thread consists of two questions:

Q#1 : What value of fault current is considered for CT saturation calculations: IEEE std is not very clear on this.
A) ASymmetrical RMS 3 Phase fault Current(RMS)- 1/2 Cycle
B) Symmetrical RMS 3 Phase fault Current(RMS)- 5 Cycle

Q#2 In the past, I have been involved in lightning protection of buildings and substations. I this project which is a oil refinery, What is the starting point of a lightning protection of a facility of this size. I am looking for some practical point of view from people, who have done this or seen what it is comprised of.

I would appreciate a word.

Thanks

 

[alehman]

1) It depends on how fast your relay operates.

2) I would start with the owner's standards and insurance company. Then look at industry standards and any local codes that might apply (NFPA 780, UL 96 and API RP 2003).

Alan
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"It’s always fun to do the impossible." - Walt Disney