Recent content by System Protection

Is that MVA for a 3 phase transformer? Or do you have three single phase transformers?

I imagine there is an interconnection agreement between the TSO and customer. The requirements should be laid out there. Not sure about any other legal requirements in Europe though or the legal authority of the TSO to impose restrictions on the breaker construction. I have not done any work...

https://www.eng-tips.com/forums/238/faqs/1287

It's an unfortunate problem. I replaced some LED bulbs that were 3 or 4 years old (intermittent use) with the exact same bulb and the difference in light output was huge.

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.