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Another way to ask the same question could be: what is the effect of deformation on the current capability of a stranded copper conductor? Agin, any references?

Hi Someone here is asking about the conformity of deformed stranded copper ground conductors in a 161kV substation. I could not find any info, but I guess there could be a problem under fault current. Is there any standard or book that gives a criterion about the acceptability of deformed cable?

First, thank you for your quick reply. Someone here told me the exact same thing but he wasnt able to tell me where it was from. Is it form any standard? Thanks again

Hi guys! Here is a question for short-circuit study experts. A small plant is fed by a 750 kVA, Yg-Yg transformer. The utility wont give X/R ratios. IEEE std C37-010 gives a typical ratio of around 7 for that transformer. Given that X1/R1 ratio, is there a way to estimate the X0/R0 ratio?

First of all, thank you The Schneider local tech gave me the TCC. FYI, ST-TE3 trip unit is in fact a ST-CM3 trip unit on a ITE breaker.

Hi guys I'm trying to learn more on motor protection. Topic of the moment: single-phasing protection. I know about standard loss-of-phase and unbalance relays. My question is: for a lightly loaded motor, say 50% of nominal HP, would a phase loss be dangerous for the motor? Because of the...

Here is a picture... Is it an obsolete Merlin Gerin breaker? What I really need is the TCC. Anyone?http://files.engineering.com/getfile.aspx?folder=8e4ce213-cce1-4e3f-89b3-3661c74f88b9&file=Photo_018.jpg

Hi everyone, Anybody knows where I could find the TCC of a ST-TE3 trip unit (on a ST-TE 600 V, 1 600 A, 50 kA breaker)? Data collection was made live, so that is all the information I could find...

dpc: thanks for the link and sorry for the spelling mistake, but english is not my first language and I cant find how to edit post. Anyone?

Thanks everyone Alehman: Why do I ask? Because someone here was looking for some reference on that topic. He has a client wanting to find the cheapest way to deal with their Yg-Yg transformers, since the local utility doesnt accept this configuration. Thanks again!

Hi all, Anyone knows a good reference that can explain what would happen to fault current and 3rd harmonic levels if the H0 of a Yg-Yg transformer is deconnected?

Hi Rockman The relay instantaneous setting (24 kA) is too high. With the tranformer power you gave and, let's say Z=7%, you have a short-circuit current of 25.7 kA, assuming an infinite source. Because of the arc impedance, the actual arcing current could be as low as 50% of that value...