Step Response of WB Cable

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Submitted by Shankar Ramharack on Sat, 02/12/2022 - 16:54
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Good day

I am attempting to simulate the response of a wideband cable that is faulted at the receiving end. However, whenever I inject a step pulse into the cable, I do not see any current reflections at the fault switch. I have double-checked the continuity, fault switching times, and signal properties.

The injected pulse is a 50V step wave with a 10ms on time. The fault is an SLG at 0s until infinity. The fault occurs on the C phase while a and b on the cable are grounded so are the sheaths.

The circuit and cable parameters are shown below I have already applied DC Correction in the fitter.

Image removed.

 

The circuit and traces are shown below

Circuit showing wb cable attatched to signal source and fault

step trace

h.gras

Hi Shankar,

Maybe you should zoom on your current waveform. If you cable is 1km, the travelling wave reflection delay would be between 1-10us I believe.

Tue, 02/15/2022 - 15:55 Permalink
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Shankar Ramharack

Hi gras,

So are you saying that the ends of the waveform where ringing is seen are actually the fault reflections? I was told that this was just switching transients. When I zoom in I see an envelope that goes to the steady-state flat line. as seen above.

Zoomed waveform of switch and fault current

Sun, 02/27/2022 - 18:38 Permalink
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