LV grid transients - an encore
LV grid transients - an encore
(OP)
More than four years ago, I needed to know about real world transients on LV grids. See http://www.eng-tips.com/viewthread.cfm?qid=207168
I am now trying to understand what IEC 60 439-1 actually says. My interpretation is here http://www.gke.org/pub/files/IEC%2060%20439-1%20tr...
But that is a lot more than I or anyone else seems to have encountered IRL. Does anyone have any new experiences? Any recordings of "Killer Transients"?
I am now trying to understand what IEC 60 439-1 actually says. My interpretation is here http://www.gke.org/pub/files/IEC%2060%20439-1%20tr...
But that is a lot more than I or anyone else seems to have encountered IRL. Does anyone have any new experiences? Any recordings of "Killer Transients"?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.






RE: LV grid transients - an encore
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: LV grid transients - an encore
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: LV grid transients - an encore
For example, here is the LV part of the table for test voltages as required by AS/NZS 2081. It shows the maximum voltage of the power circuit, the power frequency voltage withstand level (1) and lightning impulse voltage withstand level (2). Values for U(m) are in V and for (1) and (2) are in kV.
|U(m)| (1) | (2) |
| 275 | 2.5 | N/A|
| 450 | 3.0 | N/A|
|1200| 4.0 | 10 |
The power frequency voltage withstand is for 1 minute and the lightning impulse is a 1.2/50us wavefront.
But as far as transients phase to phase go, I haven't heard anything about values greater than 120% nominal. But then again, it's not really my field.
RE: LV grid transients - an encore
Your answer is in line with our experience. I am beginning to doubt the validity of the IEC 60 439-1 standard. Where, and under what circumstances can such a transient occur?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.