Recent content by System Protection

I imagine it will be a long while before we have a conclusive analysis. It's outside my realm but if I had to guess I'd say it will have to do with the "ride through performance" of the inverters. Perhaps incorrect (or insufficient) Inverter settings.

Mouser is another big supplier. What types of electronic components are you looking for?

I should clarify my comments as the transformers I used to test were autos. I could get a decently accurate reading on a short circuit impedance test with very little voltage. Just using 120VAC and a variac. The excitation requirements are less than a regular transformer though. There was...

You should be able to convert from PU to actual impedance (ohms) and calculate from there. It's been a long time since I've tested a transformer, but I'd often have to do that in reverse. Start with an actual impedance and convert to PU to check against the nameplate.

Monarch textiles sells what they call oil absorbent felt. Might be close to what you're looking for.

Any chance this started as a distribution fault? Could explain the prefault. I remember seeing some strange prefault waveforms and it was due to the underbuilt distribution faulting first. Or perhaps evolving into a transmission to distribution fault?

Another fault location method is to compare the ratio of 3I0 current from each end of the line. That should help account for fault resistance. You would use Synchrowave to get the 3I0 current from each end. Divide one end by the other. Then run intermittent faults in your fault sim program...

How are you finding the best fit with your fault program? Could the fault resistance be the reason your Z0 seems low?

Typical would be 85% reach for Phase distance and 70% reach for Ground distance for Z1.

I model it all in the line constants program that I use as its not much more effort to add the underbuild. But I don't input the mutual impedance between transmission conductors and underbuild into my fault sim program as the distribution system is not modeled. Definitely would recommend...

I checked a random spot on I10 on Street View and it showed 75MPH without a separate speed for trucks.

Single Phase Auto Reclosing I don't think its that common below 500kV. At least that I've seen in the USA.

I'll add another MC Prime annoyance. If you are paging up and your cursor lands in a text box you will enter in it and will have to click outside of the box to continue paging up.

This makes sense. Maybe their policy got lost in translation somewhere.

Nope. What would they do if a significant portion of their lines got hit with lightning? Just leave half their lines out of service? Its normal to go inspect a line that trips to lockout before attempting to re-energize but I've never seen one left de-energized after the problem was found/fixed.