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I should have written between 120% and 170%, sorry,

Hi all, Thanks for helping ! Page 16 of this presentation http://www.hv-eng.com/OvercurrentProtectionAnnex.pdf refers to NEC 240-100, that mentions that ANSI 51 can be anywhere between 100 and 600% ! It seems too high; but the PDF states that "the intent is to provide protection for...

Hi folks, Please, what is the usual practice for the ANSI 51 pick up for 4.16kV industrial (radial) feeders ? I have read people saying from 10% to 600% of the ampacity, a bit confusing, Thanks a lot, Mongao

Thanks a lot for helping, I really appreciate it !

Thanks for helping ! Please, why should I add a 5-6 seconds delay ? There is no other device (say, there isn't a NGR monitoring device in this case), so, if a fault happens, why shouldn't I clear it immediately ? Thanks again, your help is much appreciated !

Hi Guys, I have to protect a feeder with SEL-751, I was asked to do 50N and 51N, On the source side, the feeder is connected to the NGR-grounded-Wye side of a Delta-Wye transformer; on the load side it is connected to the Delta side of a Delta-Wye grounded transformer, so there is no steady...

Hi all, Please, does anyone know how to make the motor starting curve appear in ETAP's Star view ? When I "drag n drop" the motor symbol to Star, it only shows the motor cable damage line, it doesn't bring in the starting curve. I have indeed tried running a starting study before...

Thanks for replying, it's much appreciated !

Hi friends, I need to understand the SIEMENS relay 7SJ640, it has 3 "ANSI 50" functions called 50-1, 50-2 and 50-3. Please, how do these functions work together ? Let's say for example that I want the relay to trip the breaker instantaneously if the current reach 1200 A, how should these 3...

Yes.....yes.....I got the file from someone else that had set 4160 kV for the generators, of course it's 4.16 kV. The error has disappeared, thanks to everybody that helped !

ETAP help file says that, starting from the swing bus, it calculates internally the base kV for each bus based on transformer ratios. I have figured out that ETAP includes the swing bus itself in this error message, which means that it doesn't even pass it, it tries to start calculating busses...

Hi all, I am now using ETAP for the second time in my life, so I am not really used to it. I have added some busses to an existing system, but when I try to solve the flow ETAP gives me this message, saying that many busses base voltages differ more than 40% from the nominal voltages. The...

Thanks for replying !

Dear friends, I am investigating differences between live and dead tank breakers when specifying the equipment for purchase. Apart from the obvious absence of CT's in live tank breakers, are there any other significant differences between them ? How would a live tank specification differ from...

Thanks Waross, Please, do you have info about the voltage sag limit at the motor terminal bus when it starts ? Thanks, Andre

Dear all, I am in search of information related to voltage operating limits in North America, more specifically switchgears and motor terminals. ANSI C84.1 separates voltage limits in two categories, "service" and "utilization" voltages; but these refer to the voltage levels in buses...