Hi Humble2000 (Electrical)
According to Siemens "Formel und Tabellenbuch" the inrush current depends upon Rated Power .So for 3000/4000 KVA would be 6 [from 13.8 kV] and 10 supplied from 0.6 kV. The inrush current amplitude would be half of the above value for at least 10 up to 60 cycles. For 60 Hz [one cycle=1/60 second] from 1/6 up to 1 second. So for 0.1 seconds would be sure above the half.
Best Regards
7anoter4
what is siemens "Formel und Tabellenbuch" ?
Thanks for the responce though. I am also woriied about cold and hot load pick up. cold load pick up could be 15 times more right? any information on these values?
The 12x figure is a very rough approximation used to determine boundary for primary protection.
Source impedance does have an effect, as you suggest. There was some discussion here several months ago regarding a white paper by S&C that discussed this issue. You might search this forum or see if you can find it on S&C webpages.
Re: "I am also worried about cold and hot load pick up. cold load pick up could be 15 times more right? any information on these values?"
These items are different from the magnetizing inrush in both magntiude and duration. You need to differentiate if the load is a utility feeder residential, industrial load etc all of which may have much different characteristics.
JIM
Hi Humble2000
Siemens AG is well known Manufactory company for Electrical Product including High Voltage Equipment and Transformer.
The actual table [Translated] is as follows:
Siemens AG Berlin Muenchen
Formel- und Tabellenbuch für Starkstrom-Ingenieure [Formula and table book for power engineers] 1965[see attachment]
