Surge Arrester

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mrahman7

Surge Arrester

Would you please give me some clarification of the way the built-in surge arrester is working in PSCAD. I am using a 15kV rated voltage surge arrester. During the surge the should limit the voltage somewhere near 15kV. But in the simulation it is limiting the voltage at around 1.9 kV, though the voltage at the same point without the arrester is around 80 kV.

Status: Open Aug 01, 2016 - 02:47 AM

Arrester

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Mathias

Aug 02, 2016 - 05:44 AM

Hello,

After taking a look at your case it became clear that you intend to use the rated voltage setting of the surge arrester as if it were a voltage limiter. It is true that the voltage is limited by setting the rated voltage, but it will not necessarily be limited in a one-to-one manner. In other words, setting 15kV as the rated voltage does not guarantee that the voltage will be limited at that same value. If you want to configure the response of the surge arrester you need to enable the user defined I-V characteristics table in the component. From there you can enter the respective values, which are usually given by the manufacturer.

I hope this helps understand the surge arrester.

Regards,

Mathias

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Jakob_Sch

Aug 10, 2016 - 08:54 PM

Hello.
Here is what I found out on how to model and parametrize surge arresters:

In PSCAD, the "arrester voltage rating" parameter is needed to specify the voltage values of the v-i-characteristic, in which you specify pu values (the "arrester voltage rating" is the value for normalization, the base value). On surge arrester data sheats, the meaning of the value U_rated is a RMS voltage across the arrester, that it should be able to bear undamaged for a certain time (usually 10s). You CAN use this value for the parameter "arrester voltage rating" in PSCAD (and it is probably intended like this), but it is not mandatory, as "arrester voltage rating" is a mere base value for per unitizing as explained.
Otherwise, the i-axis of the v-i-characteristic has to be specified in kA.
What got me confused at the beginning is that you seem to use a rms value to per unitize peak voltage values (as the values, currents and voltages, in the v-i-characteristic are peak values). But again, "arrester voltage rating" is only a base value, it does not matter whether its meaning on data sheats is a rms value.

Hope this is useful.
J.

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Hello,
It is best to see the PSCAD file to see what is going on. Could you send it here or better yet send it to PSCAD support.

Regards,
Mathias
I cannot attach it here. This is the link to the file.
https://drive.google.com/open?id=0BzHW_Oh9YrAfMlpuaTNpY3N2V3c
Sir Mrahman7, can you help me how to design and connect a surge arrester model into a circuit? Currently, I'm doing a research on lightning protection.
I figured out something that my Lightning Surge model was not appropriate. In the previous model it was 350k KV. Now I have corrected this one to 350 kV. But now the problem is that for the 15kV arrester, it is limiting the voltage at 30 kV; for the 25 kV arrester it is limiting at 50 kV. The file is attached here:
https://drive.google.com/open?id=0BzHW_Oh9YrAfc1RtQjlUcmF6Nm8
Have you tried to adjust your I-V curve as I suggested above?
Yes, I just changed the V-I char curve accordingly, and now it is perfect. Thanks.
Hello jakob,
Thanks for the reply. In the attached file below, the peak voltages at the points of interest are 103 kV, 87 kV and 82 kV in the three phases - without the arresters.

https://drive.google.com/file/d/0BzHW_Oh9YrAfNkNRQXlFNHU5U0U/view?usp=sharing

When I am introducing a 9 kV arrester all those voltages are chopped off at around 9 kV. But if I change the arrester to 90 kV, I expected only the phase A voltage would be chopped off at 90 kV. But I see that, Phase B and C voltages are also decreasing a little.

The V-I curve is changing the value of the cut off voltages but I am not being able to make a V-I curve which would chop off the voltage exactly at the rated voltage, and the arrester would not operate below the rated voltage at all. Any suggestion?
Dear friend,
how to design a lightning surge model on 3 phase lines?

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