EN 50522 earthing of power instalations exceeding 1 kV AC - calculation of actual touch voltage

[kobiyani]

Hello,
The European standard EN 50522 is describing with full details how to evaluate the touch voltage.
Item 5.4.2 is depicting a design process which is summarized in a flow chart in Figure 5 in the standard.
In my case:
The criteria of earth potential rise (Ue) < double the allowed touch voltage is not met.
The design flow chart in leading me to take “recognized specified measures M” which are also detailed in the standard – in Annex E of the standard.
Table E.1 of the standard is attached.
My position in the table is the last bottom row (tf<5s & UE> 4 x Utp) and according to the standard I need to “Proof UT < Utp.
The problem I have is that I cannot find in the standard how to calculate UT, which is the actual prospective touch voltage.

Does anyone know where this calculation is described in EN standards (or IEC)?

 

[7anoter4]

See[for instance]:
file:///C:/Users/user/Downloads/pub16573.pdf
fig 1 page 80

 

[ScottyUK]

Whatever that file is, it is located on your C:/ drive.

 

[7anoter4]

It is very funny, indeed. However it is not my C: but of:
Ilze Priedite-Razgale1, Janis Rozenkrons2, 1-2 Riga Technical University
and if you’ll put it in Google-for instance-you’ll get the pdf.

 

[ScottyUK]

I'm not sure what term you are Googling but I can't find it other than some Russian-language site which I'm not clicking. Can you post a working link?

 

[7anoter4]

I am sorry.Try this one
file:///C:/Users/user/Downloads/pub16573%20(4).pdf
or

https://www.google.co.il/search?q=D...57.1653j0j4&sourceid=chrome&es_sm=93&ie=UTF-8

The title has to be as follows:
Development of an Algorithm and Software “MVES-TV 2012” for Touch Voltage Evaluation in MV Networks

 

[kobiyani]

Thanks for the information.
however, the figure 1 in page 80 in your mentioned file is providing the ALLOWED TOLERABLE touch voltage.
I was asking about the calculation of the actual developed tough voltage which needs to be lower than the value from figure 1.
moreover, this figure 1 is included in IEC 50522 itself.

so the mystery is still unsolved here.

 

[7anoter4]

In the above article it is written:
"If Ue>4*Utp ,then UT<=Utp is proved according to EN 50522:2010. [7], [8]"
In the list of references :
[7] Post Glover “Neutral Grounding Resistors. Technical information”
[8] Guide for Safety in AC Substation Grounding, IEEE Standard 80:2000
That means, in my opinion, UT has to be calculated according to IEEE 80/2000.
In my opinion also, nor BS7430 neither DIN-VDE 0141 presents any reference to touch and step voltage.

 

[kobiyani]

OK! now we are starting to get close.
however, the reference from IEC set of standards into IEEE is strange.
i do know the IEEE 80.
however, i am straggling to figure out the IEC methodology to handle the tough voltage, and there are gaps in the system, as far as can understand.
i really hope to find a solution within the IEC system.
maybe my effort is for nothing. I hope not.