Utility Short Circuit Data Proprietary?
Utility Short Circuit Data Proprietary?
(OP)
Hello,
I'm performing an arc flash hazard analysis for a company in California. When trying to get the available short circuit data from the utility, I was told that this information is proprietary. Has anyone else expierenced this and how did they handle it?
I think it's preposterous that this would be proprietary information, how does one properly size switchgear, protection devices, etc. without this?
amazed!
I'm performing an arc flash hazard analysis for a company in California. When trying to get the available short circuit data from the utility, I was told that this information is proprietary. Has anyone else expierenced this and how did they handle it?
I think it's preposterous that this would be proprietary information, how does one properly size switchgear, protection devices, etc. without this?
amazed!






RE: Utility Short Circuit Data Proprietary?
Mike
RE: Utility Short Circuit Data Proprietary?
HP
RE: Utility Short Circuit Data Proprietary?
Of course, this is of little help when doing arc-flash or power flow studies.
You might have to contact the PUC.
RE: Utility Short Circuit Data Proprietary?
RE: Utility Short Circuit Data Proprietary?
RE: Utility Short Circuit Data Proprietary?
Additionally, i am asking for the duty on the primary side of a customer owned transformer. As far as getting into changing transformer sizes, that would or could affect more than the arc flash, ie short circut withstands of equipment. This is a responsibility that should fall n the customer to the affects of changing out power equipment.
RE: Utility Short Circuit Data Proprietary?
RE: Utility Short Circuit Data Proprietary?
RE: Utility Short Circuit Data Proprietary?
PG&E was one of the most difficult. They made me send a signed letter request along with a service application (this was an existing service!?). There was considerable delay when the service size I listed on the application did not agree with their records. The process took many weeks and numerous phone calls, but I finally did get an answer.
RE: Utility Short Circuit Data Proprietary?
My concern with using a generic maximum possible, theorectical, design for type value is that it may not produce a conservative value for an arc flash hazard. This is because of having to reduce the bolted fault to an arcing fault which will affect trip times. So an artifically high bolted fault current when reduced to an arcing fault could trip the breaker or blow the fuse faster than would happen using values closer to actual. This could lead to choosing arc flash clothing that is inadequate. This should give the utility lawyers something to think about if they are worried about lawsuits due to giving out accurate fault current information.
RE: Utility Short Circuit Data Proprietary?
[quote]The standard calculated available fault currents are given in amperes, RMS symmetrical, at the secondary bushings of the Company's transformer, assuming an infinite bus and a bolted fault. The intent of these values is to serve as a guide in the selection of the proper service and downstream equipment. These are of no value for the use in determining the proper personal protection equipment since the impedance, fuse size and type, and calculated primary fault current available at the primary bushings of the bank can not be known for any particular installation.[quote]
Don
RE: Utility Short Circuit Data Proprietary?
RE: Utility Short Circuit Data Proprietary?
Don