Prospective permissible touch voltage in acc. to EN50522

[PeZeKa]

Dear all,
I have read discussion between IrishPower and radug.
thread238-305712

Unfortunately I face the same problem - how given in figure B.2 /Annex B/ curves are calculated?
In standard EN50522 equations missing.

Will be great if someone can help.

Best regards!

 

[IrishPower]

Hi PeZeKa,

The EN50522 standard doesn't make things easy, but it is possible to recreate the curves in Figure 4 and Figure B.2 using the equations shown in Annex A and Annex B (with more accuracy at some points than others...), and to use the same process to come up with alternative curves if required.

You will see from the previous discussion that radug was able to get reasonably close to matching the results for Figure 4, and we ended up getting similar results ourselves for more data points using MS Excel and VLOOKUP functions. We came to the conclusion that the differences between our results, radug's results and the sample results shown in Table B.3 of the standard are most likely due to rounding/simplification of some of the input data shown in Table B.1 and Table B.2 compared to whatever input data Figure 4 was actually based on. We got differences of up to +/- 8 % between our calculated values and the Figure 4 values (for some fault durations only; most values were much closer).

The Figure 4 curves are calculated by averaging weighted results of the four different cases described in Note 1 of Annex A of the standard. Once you have the methodology for this figured out, by comparison working out the results for Figure B.2 becomes a lot easier...

Hope this helps - best of luck!

IP